Public urban development policies have a long-term impact on the availability, location, cost and affordability of housing, and hence on the residential trajectories of individuals in different social groups. Using data from several quantitative and qualitative surveys, the authors show how the development of transport infrastructures in the Paris region over the 20th century played in important role in reshaping the spatial distribution of populations over time. The cohorts born between 1911 and 1950 and the different occupational categories were affected unequally, be it positively or negatively, by transport development, urban sprawl, and rising property prices in Paris.
1While long seen by demographers and sociologists as a simple backdrop to human activity, geographical space and its transformations are central to the issues of spatial mobility and social reproduction. Space is simultaneously a reflection of social structures, a structural component of social relations, and a social construction (Halbwachs, 1938; Lefebvre, 1974). Among the numerous political and economic actors (decision makers, urban developers, private promoters, etc.) who shape geographical space, individuals and households play a pivotal role as they adapt to changes in their environment, grasp the opportunities offered by housing policies, and adjust their mobility strategies to the constraints of the property market.
2Research on residential segregation processes (Bacqué and Lévy, 2009), on the ‘place effects’ (Frémont et al., 1984; Bourdieu, 1993), and on ‘residential choices’ (Bonvalet and Dureau, 2000; Authier et al., 2010) has shown the importance of spatial characteristics in shaping residential and social mobility. The neighbourhoods inhabited since childhood are a framework of socialization that can influence lifestyle choices, residential aspirations, and social trajectories. The physical and social characteristics of space also act upon social mobility by attracting or repelling population categories. Individual geographical trajectories therefore cannot be understood without reference to their associated social trajectories. In an agglomeration, place of residence can be seen as a component of social status, notably via the physical characteristics of the residential environment and its proximity to urban resources (jobs, shops, transport, public amenities, etc.), or via the prestige of the location, the image of the neighbourhood, and its social characteristics. It thus confers a certain socio-residential status upon households in the agglomeration (Bonvalet and Fribourg, 1990; Lévy, 2003) and establishes their position in the social hierarchy (Bourdieu, 1993; Cailly, 2007).
3Since Halbwachs, social divisions of space in the Paris region (Île-de-France) have been widely studied by sociologists and geographers (George, 1950; Chombart de Lauwe, 1952; Bastié, 1964). The east–west divide that they brought to light when the agglomeration was still relatively small became increasingly complex as the pace of urban sprawl accelerated in the second half of the 20th century (Berger, 2004). From the 1970s, some sections of the working-class population found themselves progressively relegated to poorly served peripheral municipalities, while others could remain in or move into more central districts or municipalities that, while increasingly gentrified, still provided access to social housing (HLMs)  and properties rented under the 1948 law.  In parallel, the deindustrialized districts of central and eastern Paris, followed by those of the southern and eastern inner suburbs, gradually moved upmarket (Préteceille, 2006; Pinçon and Pinçon-Charlot, 2008). Since the early 1980s, a large body of research has focused on these transformations, based mainly on the analysis of cross-sectional aggregated census data, and several phenomena have been brought to light (Tabard and Bessy, 1990; Rhein, 1994; Préteceille, 2006; Clerval, 2013). These include the gentrification of Paris  and its adjoining municipalities, the continued existence of mixed neighbourhoods with a spatial regrouping of working-class and middle-class populations, and a social polarization of municipalities in the Paris region.
4In this article, we analyse these urban processes by following different birth cohorts and studying their contribution over time to the redistribution of social groups across the Paris agglomeration between 1930 and 2000. This cohort-based historical approach is founded on the analysis of geographical and social trajectories viewed as a succession of socio-residential statuses. We focus on ease of access to places of residence and how it has changed with the expansion of the transport networks (Merlin, 1997). We posit that changes in the accessibility of urban spaces are key determinants of residential choices across successive generations of different social groups and have structured the social divisions of space. To what extent have these generations and social categories adapted to, or taken advantage of, the expansion of transport infrastructures? Who were the pioneers of periurbanization, and what characterizes the people who remained in or moved into the most accessible spaces?
5This article draws on a corpus of INED life-event history surveys (Box). Section I presents the approach taken to study inequalities in access to Paris based on analysis of individual geographical trajectories along with the development of the regional transport infrastructure and its impact on the geographical trajectories of cohorts born between 1911 and 1950. Based on a quantitative and qualitative analysis of social trajectories, Section II examines the process of social and spatial sorting at play and the role of accessibility in the residential choices of the different social groups living in Paris and its suburbs.
Box. Parisian ‘Fresque’ project: data and method
The qualitative analysis is based on a corpus of interviews with 183 people who took part in the PDP and BE surveys. The aim was to obtain complementary qualitative and retrospective information by conducting in-depth interviews with a subset of the original respondents to flesh out their life histories.
I – Transport networks and trajectories of successive cohorts in the Paris region over the 20th century
6A key transformation affecting the French capital over the 20th century was urban sprawl, with peripheral municipalities steadily swallowed up by expanding urbanization. Its acceleration in the second half of the century created a stronger divide between places of residence and work, and fragmented life spaces. We therefore posit that the accessibility of place of residence, as defined by levels of public transport provision, became a key factor in the residential choices of Paris region inhabitants and, for this reason, played an important role in processes of social and spatial sorting. This section analyses the development of transport networks and the way successive cohorts used or benefited from them.
1 – Urban sprawl and transport infrastructure development
7The development of transport infrastructures to accompany the expansion of the Paris agglomeration proceeded at a variable pace (Merlin, 1997). To study this process, we classified the municipalities in the region and the arrondissements of Paris  by level of accessibility, as defined by the availability of transport services and infrastructure. This breakdown differs from the administrative divisions habitually used (Paris, inner suburbs, outer suburbs). It defines a relative position in the region at a given moment, but which is liable to change over time: a municipality may be considered as peripheral at the start of the century but become increasingly central due to urban expansion, suburban densification, and transport network development. These levels of accessibility can then be matched against data from censuses and life-event history surveys.
8To determine these levels of accessibility, we retraced the development of the region’s major transport networks over the 20th century—underground network (métro), regional express commuter network (RER), rail network (Société nationale des chemins de fer français [SNCF]), and major roads (motorways and expressways).  Using open-access geodata (available on the websites of the Atelier parisien d’urbanisme and the Institut d’aménagement et d’urbanisme), we documented their dates of opening (and closure in some cases) using different sources.  For each year between 1900 and 2001, we drew up an inventory of the services available in the Paris region municipalities and the Parisian arrondissements for each type of transport.  Based on this information, municipalities were divided into eight categories according to the frequency and speed of services on each network (Figure 1): dense underground (two or more stations per hectare and easy access to the other networks); less dense underground with RER; less dense underground without RER; RER without underground; railway and expressways; railway without expressways; expressways without railway; no transport network.
9As Merlin (1997) observed, infrastructure development took place in several stages. In the early 20th century, the underground developed inside Paris, providing a dense transport network for inhabitants of the city. The Paris suburbs, still sparsely populated, were structured by the presence of industrial activities close to the rail network. The interwar period marked a turning point, with the growth of suburban residential districts that were poorly served by the transport network, and with infrastructure development in general (Faure, 1991; Fourcaut, 2000).
10Following the Second World War and the housing crisis in Paris, the suburbs became more densely urbanized beginning in the mid-1950s, with the construction of high-rise developments on unoccupied land. From the 1950s and 1960s, a growing network of motorways provided new transport links to certain peripheral municipalities and improved the accessibility of those located along radial axes already served by the rail network.
11The 1965 urban development plan for the Paris region (Schéma directeur d’aménagement et d’urbanisme de la région de Paris) marked a shift towards polycentric development of the agglomeration, with the construction of new towns  in tandem with the development of the RER and of urban motorways serving the suburbs. This phase began in the 1970s and continued to the end of the century. In parallel, periurbanization received new impetus following the 1977 housing finance reform designed to improve access to home ownership for low-income households. From the late 1960s, transport networks in the Paris region underwent two major developments: first, the progressive opening of the RER lines from the early 1970s to the 1990s, their connection with the underground lines, and the concomitant extension of the underground into the inner suburbs; and second, the development of the national and regional motorway network (along radial axes and in concentric circles around Paris, respectively).
12The first major development gave rise to two new types of accessibility: ‘RER without underground’ and ‘less dense underground with RER’ (Figure 1A). In 2000, more than half of the Paris region population lived in municipalities belonging to one of these categories. Despite the acceleration of urban sprawl, this change marked a general improvement in residential accessibility for the region’s inhabitants. Occurring over a period when the Paris agglomeration population increased by two million (natural growth and in-migration), these changes led to a population redistribution towards the suburbs.
Transport infrastructures of Paris region municipalities in 1940, 1970, and 2000
Transport infrastructures of Paris region municipalities in 1940, 1970, and 2000
2 – Accessibility of places of residence across cohorts
13These developments in housing and transport provision took place throughout the lifetimes of the cohorts born in the 20th century. Improved access to the city broadened the residential choices open to households and modified their living environment, even for those who did not move. Contextual, political, economic, and macrosocial transformations were additional factors in the different cohorts’ residential choices and aspirations. The aim here is to analyse the changes in transport provision and their effect on the geographical trajectories of cohorts born between 1911 and 1950.
14Recorded on the scale of municipalities and Parisian arrondissements, the respondents’ trajectories can be analysed in terms of the accessibility of their successive municipalities of residence.  The study is limited to trajectories between ages 20 and 50, an age span that minimizes both right censoring (start of the independent residential trajectory) and left censoring (age of the youngest respondents) for all three surveys. The study cohorts were chosen to isolate meaningful cohort groups, taking account of the context at the time of family formation when couples are seeking residential stability: the 1911–1925 cohorts (3B), the 1926–1935 cohorts (PDP), and last, the 1936–1945 and 1946–1950 cohorts (BE).
Accessibility of municipalities of residence in the Paris region by age and by cohort
Accessibility of municipalities of residence in the Paris region by age and by cohortNote: The dotted vertical line indicates approximately the year 1970. It is used as a reference to place the trajectories of the various birth cohorts in their respective contexts. The year 1970 was chosen because it corresponds to the first urban development policies at the regional level and the opening of the RER commuter lines.
Coverage: At each age, only respondents present in the Paris region are considered.
15For each cohort, the chronograms in Figure 1B give the proportion of individuals living in each accessibility category by age between 20 and 50. The breakdown by cohort reveals a diversification of the accessibility categories of respondents’ places of residence across cohorts and reflects the prevailing contexts. Over their lifelong geographical trajectories, the oldest cohorts (1911–1925) were divided between one half who lived close to an underground station and the other half who lived close to a railway station in what was then the suburbs. After the war, however, more frequent settlement in the most central arrondissements and municipalities (with dense metro access) can be partly explained by the arrival of young migrants from the provinces or abroad.
16It was in the 1926–1935 cohorts that the largest proportion of households left the most accessible districts. The post-war housing shortage (Chombart de Lauwe, 1952) obliged many young people setting up home to move into the suburban housing estates and high-rise developments that were mushrooming in the peripheral municipalities served by the rail network.
17The RER and the ‘new towns’ arrived at distinct moments in the lives of the different cohorts. The RER came into service when the baby boomers were having children, enabling many of them to move to newly accessible suburban municipalities. The rapid increase in the share of individuals aged 30–35 living in municipalities served by the RER was linked not only to new housing developments in the new towns but also to the housing finance reform of 1977.  Thanks to the RER, it became easier for the 1936–1945 cohorts to find suitably sized homes for their families or to commute to work with greater speed and comfort. The RER had little impact on the trajectories of older cohorts, often already settled in Paris or its suburbs.
18For all these cohorts, particular moments in the life course are affected by contextual changes such as marriage, family formation, or arrival in Paris for those migrating from elsewhere. While a large share of the cohorts born in the early 20th century migrated to the Paris region, not all cohorts were affected to the same degree by the housing crisis that ensued. Likewise, the different cohorts did not all benefit simultaneously from access to housing loans from the 1950s, mass housing construction in the 1960s, the construction of the RER, or the 1977 reform. Moreover, each cohort was marked by a specific economic and political context (belle époque, interwar period, post-war boom, etc.). They also witnessed periods of major structural change in the job market, including women’s mass entry into the labour force and the shift from manufacturing to services. The successive cohorts thus lived in different contexts, not only in terms of transport and housing, but also with regard to housing support policies and the rapidly evolving production system, whose impact on social and spatial mobility may have differed according to each household’s position in the social hierarchy.
II – Geographical trajectories of cohorts and biographical social categories
19How does the development of transport infrastructure affect segregational processes (Bacqué and Lévy, 2009; Coulton and Turner, 2012; Bailey et al., 2017) and how does accessibility of transport influence the cohorts’ residential choices across different social categories (Raymond et al., 1966; Bassand and Kaufmann, 2000)?
20Cross-sectional census data harmonized from 1968 to 1999 for the working population aged 25–54 show both a change in the occupational structure and a redistribution of the various occupational categories in the Paris region. This took the form of a numerical increase in higher-level occupations (executives, professionals and intellectual occupations), most notably in the most accessible parts of the agglomeration; a strong increase in intermediate occupations and in clerical/sales workers, except in Paris intra-muros where their numbers were static; and a drop in the number of manual workers, more pronounced in the central zones than in the rest of the Paris region. These changes are complex. They are explained by transformations of the production system (deindustrialization, service sector expansion), but also by the arrival of the highly educated, socially and residentially mobile baby-boom cohorts on the Parisian labour market (Bonvalet and Ogg, 2009). To show how these changes in occupational structure were associated with a geographical redistribution of social groups, we ran a longitudinal analysis combining residential and social mobility for the different cohorts.
21But this calls for prior reflection about the social categories that can be used in such longitudinal analyses. Research on spatial segregation and residential choices has clearly demonstrated that social status is an important determinant of residential opportunities, aspirations, and constraints. And in France, numerous sociological studies have shown that occupational categories reflect one’s position in the social hierarchy (Desrosières and Thévenot, 1988). It would be an oversimplification, however, to use the social status of individuals at a single point in time (as defined by their occupational category at the time of the survey) to study the residential trajectories that interest us here. Occupational status evolves over the life course and individuals may wish to change their place of residence to take account of their new social position. Moreover, research on the process of social reproduction has shown that the parents’ occupational and residential status influences the trajectories of their children (Bertaux and Bertaux-Wiame, 1988; Bonvalet and Gotman, 1993). It is important, therefore, to look beyond the occupational category at the time of the survey and to construct categories that take account of inter- and intragenerational social mobility.
22In addition, while social status is traditionally assigned at the household level and based solely on the man’s position in the case of couples, its definition at the couple level is more appropriate for the study of residential trajectories, given that residential choices are made jointly by couples, taking account of each partner’s resources and constraints. For couples, we therefore took the partner with the higher occupational level as a reference for determining social status.  The social mobility categories were constructed using information available in all three quantitative surveys: father’s occupation at the end of his working life and the occupations of the respondent and his or her last partner (if not single) at the start of their working life and at the end (or at the time of the survey), each coded into one of seven groups. Our method is based on the standard mobility tables used to describe intergenerational mobility (Erikson and Goldthorpe, 1992), also applied here to intragenerational mobility, using an adaptation of the hierarchy and mobility table constructed by Peugny (2007). Six ‘biographical social categories’ were defined:
- Stable working classes: the father’s last occupation and the couple’s entire working careers are in the farmer, manual worker, or clerical/sales worker categories;
- Downwardly mobile working classes: couple in farmer, manual worker, or clerical/sales worker categories at the end of their career, with inter- and/or intragenerational downward mobility;
- Upwardly mobile middle classes: couple in self-employed or intermediate occupations at the end of their career, with inter- and/or intragenerational upward mobility;
- Stable middle classes: the father’s last occupation and the couple’s entire working careers are in the self-employed or intermediate occupations;
- Upwardly mobile upper-middle classes (classes supérieures): couple in higher-level occupations (in French: cadres, professions intellectuelles supérieurs et chefs d’entreprise), at the end of their career, with inter- and/ or intragenerational upward mobility;
- Socially reproduced upper-middle classes: the father’s last occupation and the couple’s entire working careers are in higher-level occupations or, under certain conditions,  the self-employed category.
23In our sample, these categories demonstrate the relative expansion of the upper-middle classes across cohorts and of the important role of social mobility: the upwardly mobile upper-middle classes represent 15% of the 1911–1926 cohort and 22% of the 1946–1950 cohort.
24Cohort effects of access to Paris combine with a social hierarchy effect (Figure 2), position in the social hierarchy being closely correlated to the hierarchy of residential accessibility. The most advantaged social categories more frequently live in the most accessible locations than the least advantaged categories. From one generation to the next, increasing heterogeneity in levels of accessibility between different residential areas is associated with a widening accessibility gap between the two extremes of the social hierarchy. At age 50, in all birth cohorts, around half of the socially reproduced upper-middle classes live in the most accessible areas (dense underground) (Figure 2, bottom row), while among the stable working classes, the proportion drops from one-third to one-fifth between the oldest and youngest cohorts (top row).
Accessibility of municipalities of residence by age, social category, and cohort
Accessibility of municipalities of residence by age, social category, and cohortNote: The dotted vertical line indicates approximately the year 1970. It is used as a reference to place the trajectories of the various birth cohorts in their respective contexts. The year 1970 was chosen because it corresponds to the first urban development policies at the regional level and the opening of the RER commuter lines.
Coverage: At each age, only respondents present in the Paris region are considered.
25The combined cohort and social hierarchy effects reveal three other major tendencies (Figure 2): first, among the upwardly mobile middle and upper- middle classes in the 1926–1935 cohort, a movement away from the most accessible areas to more peripheral areas after age 30 (second column, third and fifth rows); second, among the stable and upwardly mobile middle classes in the 1946–1950 cohort, a sharp increase at around age 30 in the proportion living in suburban areas served by the RER (last column, third and fourth rows); and third, a non-negligible proportion (around 15%) of stable working classes with no rail transport access (first row) that remains constant across the cohorts. These phenomena are detailed in the following sections and illustrated by accounts from the in-depth interviews. These examples were selected based on the respondents’ birth cohorts, geographical trajectories, and inter- and intragenerational trajectories. Their narratives shed additional light on the rationales for residential choices and on the strategies deployed in the context of their personal life histories.
1 – The decline of the ‘working-class’ in Paris after the 1960s despite households’ strategies of resistance
26The working-class presence in the most central districts of the agglomeration decreased during the second half of the 20th century as a combined result of several factors (Figure 2), notably changes in the occupational structure which reduced the relative share of manual and clerical/sales workers in the population (Chauvel, 1998), and departures from Paris intra-muros from the 1960s onwards, especially among the cohorts born after 1926. Placed in context, these trajectories can be explained both the decreasing availability of affordable dwellings inside Paris as the city started renovating its rundown neighbourhoods and, conversely, the increasing availability of social housing in suburban high-rise developments often built to accommodate manual workers. Paule’s trajectory is a typical example. Born in 1950 and abandoned at birth, Paule spent her teenage years in a children’s home run by the departmental health and social services (Direction départementale des affaires sanitaires et sociales [DDASS]) in Paris.  She would have liked to stay in Paris after getting married, but the couple had no choice but to accept an HLM apartment offered by the Peugeot company in Poissy (an industrial suburb 30 km north-west of Paris) where her husband worked as a mechanic. Classed in the stable working-class category (Paule has a lower-secondary florist’s diploma), they found refuge in social housing outside Paris when their children were born (Figure 2, fourth column, first row).
27In parallel with this movement to the suburbs, much of the working-class population in Paris intra-muros born after 1940 stayed put, thanks mainly to the existence of social housing which allowed manual-worker households to remain in the capital. Serge’s story is a remarkable example of both social and residential mobility. ‘I was born in the neighbourhood, I went to school in the neighbourhood, I met my wife in the neighbourhood…She was born here too. So, there you are, we’ve never been apart.’ Born in 1942, Serge worked at a printer’s, then in the banking sector, and has practically always lived in the same HLM apartment block in the 20th arrondissement, a working-class district of eastern Paris. His parents had moved into a newly built HLM housing project on the boulevards des Maréchaux in 1934.  His father, a building worker and then a shopkeeper, died when Serge was 16, leaving him alone with his mother in the apartment, his four sisters having already moved out. When he married the neighbours’ daughter, whom he had met at nursery school, his mother left them her own apartment, which was too large for her alone. Three years later, after the birth of Serge’s two children, his parents-in-law retired and left their four-room apartment to the young couple. Serge and his family are living there to this day. Serge and his wife were thus able to stay in their neighbourhood and move into a larger apartment as their family grew, simply by replacing the previous generation. ‘You just had to change the name on the rental contract.’ But it was also the result of a choice, that of staying in social housing to remain in the neighbourhood where they were born. ‘A long time ago, if we’d wanted a house, we would have bought a house. But I didn’t want to leave Paris. I didn’t want to leave my neighbourhood. I didn’t want to buy.’
28The role of family networks in obtaining social housing or a rent-controlled apartment under the 1948 law is mentioned in numerous interviews. Parents, uncles, aunts, and colleagues are all solicited, and complex strategies are deployed to obtain and keep a dwelling (Loiseau and Bonvalet, 2005). Affordable rents for social housing or 1948 homes, lower than those charged in the private rental sector, have enabled tenants who would otherwise be excluded for reasons of cost to stay in centrally located upmarket districts of Paris. Given the facilities at their disposal and the comfortable lifestyle in these old central districts, they preferred to give up the chance to buy rather than ‘go into suburban exile’.
2 – Continued upper-middle-class presence in central districts across cohorts
29The continued presence of the socially reproduced upper-middle classes in the most accessible areas from one generation to the next is associated with a relative increase in their share in the populations of these areas. In the older cohorts, the socially reproduced upper-middle classes, like other social classes, were forced to move to the suburbs due to the post-war housing shortage. However, in the younger cohorts, this is the only social class among whom a large proportion has the means to live in central districts of Paris. This continued presence is not linked solely to personal wealth but above all to family assets and/or networks, particularly when the family is Parisian. Urban renovation policies and the expansion of the underground to cover largely working-class districts have contributed to the attractiveness of Paris and made it even more desirable to continue living in the city. Homeowners in the different cohorts have benefited from rising property values and an improved living environment thanks to these rehabilitation policies and to the arrival of public transport in formerly isolated Parisian districts. The set of advantages of living close to the vast array of Parisian amenities is another argument for staying in the city, even if it means staying in the rental sector.
30The residential trajectory of Michèle, manager of a home furnishings store, born after the war into a bourgeois family from Grenoble (a medium-sized city in south-eastern France) is an example of the socially reproduced upper-middle classes. After graduating from Sciences Po in Grenoble, she accomplished her dream of ‘coming to Paris and living in Paris, that was my absolute objective.’ She then spent 3 years in the heart of the Parisian student quarter, in an apartment on the quai Saint-Michel found via a bridge-playing friend of one of her great-aunts. These were very happy years when, like many other young people of her generation, she ‘discovered new freedom’. She then married a high-ranking civil servant, and together they were able to buy a home, but in the less upmarket 12th arrondissement of south-eastern Paris:
I didn’t like the neighbourhood at all. It was very working-class and far from anywhere. I wasn’t used to living far from the centre, far from my job. I worked in Neuilly [an affluent municipality in the western inner suburbs]; it was awful!
32She nonetheless stayed there until she divorced in 1978, after the birth of her son. Without the personal means to buy a flat in a district she liked, she rented an apartment in the 9th arrondissement, close to an underground line that took her directly to her place of work. But with just one bedroom for herself and her son, the apartment soon became too small. She moved out after 3 years because she did not think much of the local schools. A cousin suggested she move into a vacant apartment in her building. Her new neighbourhood on the rue Saint-Martin in the central 4th arrondissement was exactly to her liking: a pedestrianized street, a top-floor apartment with a terrace, an old district with many shops, and located close to her work.
33While Michèle knew she could not afford to buy a property in central Paris, she exploited all the opportunities offered by successive laws promoting buyto-let investment:
I’m not a property owner at heart. I have the instincts of one, when it comes to investment schemes supported by the government—the Besson laws and so on, Méhaignerie or whatever, Périssol.  I’ve done all that, but I prefer to put tenants in these places because they’re usually in districts I don’t like, given my income.
35As this example confirms, not only owners seek to optimize their investments. Some tenants, like Michèle, weigh the advantages and drawbacks of ownership versus rental and rationally choose to remain in the private rental sector and invest in property elsewhere. And while property ownership has never been a status symbol for Michèle, her choices bear the traces of a traditional preference for rental among the French urban bourgeoisie (Daumard, 1996), but also the effects of family transmission, since her parents never bought their home in Grenoble.
3 – Upward mobility as a driver of suburban settlement in the 1960s
36The gentrification of Paris from the 1960s accelerated as the working- and middle-class cohorts born in 1926–1935 moved to the suburbs (Figure 2). It was the upwardly mobile classes whose numbers fell most sharply in the most accessible areas and, conversely, increased most strongly in the municipalities served by the rail network. This movement (from central areas to the suburbs accessible by train) was massive; around 10% of the 1926–1935 cohort followed this type of trajectory (Le Roux et al., 2017). Upward mobility was expressed in the desire to buy a house, even if this meant moving to a suburb with poor transport links and accepting a radical change in lifestyle. The case of Yolande in the 1926–1935 cohort, classed in the upwardly mobile upper-middle-class category (Figure 2), illustrates this link between upward social mobility and homeownership.
37Yolande was born in Lorraine in 1935 and spent her childhood between her mother, who left her father to live in Paris when she was 2 years old, her aunt, and a boarding school where she was placed at age 5. When she was 15, she went to live with her mother in a boarding house where she met her future husband. Although he got a job as an RATP ticket collector  through his brother, the couple could not afford to rent in the private sector and stayed on in the boarding house after their daughter was born in 1955. One year later, Yolande found a position as a caretaker and moved with her husband into a caretaker’s lodge in the 15th arrondissement, where they stayed for two and a half years. ‘And as we didn’t really know what to do, we said to ourselves, “Why not be caretakers?” No jobs were below us.’
38In 1959, they moved into a comfortable 33-m2 apartment in the building, offered to them by friends moving to the provinces. Over the next 10 years, Yolande’s husband started taking evening classes while continuing to work at the RATP. He was promoted to ticket inspector, and Yolande found a job as a chemist’s assistant via a friend. Their income was now large enough to think about buying a place to live.
39Thanks to their accumulated savings and a mortgage guarantee provided by the RATP, their dream came true in 1969 when they bought a 72-m2 apartment in Savigny-sur-Orge (a suburban municipality 19 km from Paris served by the rail network). For Yolande, who had always lived in the capital, the decision to leave Paris was difficult, especially because she did not drive:
At that time, I worked in Fresnes [a municipality 12 km south of central Paris], and the means of transport from suburb to suburb was pretty awful. So it took me an hour and a half to get home… and it was a really empty place, where I was scared stiff in winter, so I said to my husband, ‘I don’t think much of it, but well, I’ll have to learn to drive. This won’t do.’
41Unlike Yolande, who adapted well to her new surroundings once she got her driver’s licence, her husband was unhappy in the new apartment and hated the lack of space and greenery. His career was advancing well at the RATP, and he jumped at the chance when a colleague told him about a house for sale on his street. The house turned out to be small (52 m2) and the garden narrow, so the couple soon started planning to move again. Five years later, having increased their savings capacity after the husband was promoted to general inspector, the couple bought a 92-m2 house in Ollainville (a municipality 32 km south-west of Paris served by a major road) with a large garden (1,500 m2).
42At the end of the interview, Yolande acknowledged her husband’s upward mobility: ‘He leads the entire inspection service…Ah, he’s done really well for himself. Really, for someone with just a primary school certificate’. Yolande and her husband are both of working-class origin but now form part of the upper-middle classes. Their exceptional occupational trajectory has taken them on an upward residential trajectory, from a boarding house to homeownership via a caretaker’s lodge, a rented apartment, and a first acquisition. For Yolande, who spent her entire childhood in a boarding house and a boarding school, her house is the dream of a lifetime: ‘I feel happy in my home. In fact, now it’s really the…My dream has come true.’
4 – Arrival of the upwardly mobile working- and middle-class babyboom cohorts in the new towns and suburbs served by the RER
43The project to develop new towns in the Paris region was highly original in its ambition both to improve the housing conditions of suburban residents and to facilitate access to the centre of the agglomeration through the development of the RER express commuter lines. Construction began at a time when homeownership in the Paris region was expanding.  For many young first-time buyers, particularly those of the baby-boom generation, the new towns provided an opportunity to acquire a first house or apartment (Imbert, 2005).
44Géraldine, a nurse who belongs to the stable middle-class category of the 1946–1950 cohorts (Figure 2) spent most of her childhood in Boulogne-Billancourt and Châtillon (inner suburban municipalities to the south-west and south of Paris, respectively) before renting an apartment in Créteil (inner suburban municipality to the south-east of Paris) when she started living with her partner. In 1980, when she was 34, they moved with their two children into a new house in Noisiel (a municipality of the new town of Marne-la-Vallée, 20 km east of Paris) that they bought with a subsidized loan. She describes their installation in the new town as an upward residential move in terms of the living environment because she and her partner were looking for somewhere quiet, close to parks and woodland, and accessible:
Afterwards, we realized that living in the new town had an enormous advantage because the schools were just over the road…here the school is next door, the nursery school, oh! It’s great! They went to school and came home too on their own. Ah, not many people can do that! Here, we have all the advantages: living close to the RER, 20 minutes from Paris, the nursery and primary schools nearby, the secondary school nearby, the high school nearby…
46For Géraldine, who has always worked in the 11th arrondissement, her new life in Noisiel represented a major improvement over that in Créteil and even in Châtillon, which was not yet connected to the underground. With hindsight, she does not regret the early ‘pioneer’ years in Noisiel, from 1980 to 1983, before the RER station opened. She was working nights and went to work by car. At the time of the interview, access to amenities was still an important factor when she talked about her retirement plans. Considering all the advantages of Noisiel (theatre, cinema, swimming pool), her husband was even less inclined to move away than she was. By targeting the aspirations of middle-class baby boomers—easy access to local amenities, schools, cultural and sporting activities—the new towns have contributed to their spatial anchoring in these municipalities (Imbert, 2012). For Géraldine, access to amenities in Noisiel was better than in the municipalities of the inner suburbs where she had lived previously. This example illustrates how the baby-boom cohorts and their successors have benefited from the improved infrastructure resulting from the development of new towns.
5 – Certain working-class populations remain geographically isolated
47The last major phenomenon revealed in Figure 2 is the concentration of a non-negligible share of the working-class population in areas poorly served by public transport. Around 15% of Paris agglomeration inhabitants in the stable working-class category, whatever their age or birth cohort, are not connected to the rail network. Apart from a few exceptions, this concentration on the margins of the agglomeration is specific to the working classes, whose residential choices are constrained by the cost of land. This results in long commuting times into Paris, as revealed in several interviews. ‘We made the sacrifice of travelling time, but, well, we made a choice, didn’t we? From the start, we knew there was a transport problem,’ explains Annie (1947), born in the Loire department and a resident of Beaumont-sur-Oise in the north of the Paris region. She met her husband at a large company in her hometown, and the couple then decided to move to the Paris region. The husband, who was the first to leave, found a job, then a studio apartment in northern Paris after several months in a boarding house. This studio became their ‘first little nest’. After 6 months in a small one-bedroom apartment in Villeneuve-la-Garenne (a municipality 12 km north of Paris), which was dingy, dirty, and far from their place of work, they found a two-bedroom apartment in Montigny-les-Cormeilles (a municipality 30 km to the north-west of Paris, served by a motorway). They moved again to a three-bedroom apartment in the same neighbourhood when their second child was born. When the third child arrived, they started thinking about buying a home. ‘We were at the right age to buy.’
48After deciding to buy, they had to choose where to live and, above all, how much building land to buy. After visiting several places well served by trains from the Gare du Nord (the North Station in Paris), they opted for a 400-m2 plot in a municipality on the edge of the Paris region. ‘We took what we could afford.’ The price to pay was 3 hours of daily commuting for her and 4 hours for her husband who works in Puteaux (a suburb adjoining the west of Paris) and the lack of any real town centre. ‘There’s not even a town centre; you can’t even call that the town centre. It’s the street for the station, and that’s about it.’
49Despite the high inflation of the 1970s, the monthly mortgage repayments remained a constant burden because both spouses had episodes of unemployment over a 10-year period. In this case, the couple achieved their ambition to own a house and a plot of land, but had to make major sacrifices.
50Since the 1960s, the expansion of the transport network has accompanied a process of population deconcentration in the Paris region by creating residential opportunities in new locations for all social categories. It has also led to a strengthening of the link between social status and distance from Paris intra-muros at the two extremes of the social hierarchy. We analysed this link taking account of the improvements in transport provision that have changed the degree of centrality of municipalities in the Paris region over the last century. Classifying municipalities by accessibility enabled us to determine the relative status of residential locations across the agglomeration at a particular moment in time.
51The cohort approach showed how the transformation of transport infrastructures modified geographical trajectories and influenced the redistribution of social classes across the Paris region. Across cohorts, specific choices of location are linked to experience, the constraints of housing supply, and residential aspirations. Not all cohorts contributed equally to the centrifugal dynamics and to the differences in residential choices between social groups. Analysis of the successive cohorts reveals, for example, the impact of the housing crisis in Paris on decisions by certain cohorts (1926–1935) to move to the inner suburbs, or of the development of the RER on movements towards the outer suburbs among the 1946–1950 cohorts. Our results add some nuance to research claims that the role of accessibility in residential choices is secondary with respect to housing characteristics and living environments (Molin and Timmermans, 2003; Schirmer et al., 2014). In fact, the hierarchy of factors determining residential choices varies across birth cohorts and social categories, and according to individual situations. For the middle and working classes, for example, the desire to buy, strongly dependant on the availability of affordable homes and building plots, may be a more important factor than proximity to transport networks, whereas among the upper-middle social classes, a central location is sometimes the key factor, even if it rules out homeownership or calls for compromises on dwelling size.
52The joint analysis of geographical trajectories and social mobility using biographical social categories reveals marked differences regarding residential location: a stronger tendency to remain in Paris for the socially reproduced upper-middle classes than for the upwardly mobile upper-middle classes; more frequent homeownership in suburbs with a good transport network among the upwardly mobile middle and upper-middle classes than among the stable classes.
53Our analyses reveal preferences for immobility and staying put in areas where living conditions are improving, an aspect sometimes overlooked by studies of residential mobility. They also demonstrate the capacity of households to act in anticipation of future developments (especially in the transport system). When individuals are immobile, their social and residential status may be redefined or enhanced by transformations in their living environment (Coing, 1966; Dureau et al., 2006; Lambert, 2012). If individual and spatial dynamics are analysed in combination, then spatial immobility can be viewed as an active process (Coulter et al., 2016). For example, at times of general centrifugal movement, the geographical immobility of the socially reproduced upper-middle classes, analysed by Pinçon and Pinçon-Charlot in 1990, illustrates the strength of the intergenerational transmission of social status and residential standing.
54The residential trajectories of the 1911–1950 cohorts took place under exceptional conditions of upward social mobility and expansion of housing choices in terms of location and occupancy status. Their histories reveal the complex, dynamic relationships of social and residential positioning at play between generations and social classes.
Method used to ensure comparability between the 3 surveys
55To study the settlement of the Paris agglomeration over the 20th century, it is important to consider the processes of depopulation within Paris and of suburban development, both of which accelerated from the 1950s. The aim is to see an agglomeration as a functional unit in terms of the housing and employment markets and to take account of the progressive incorporation of secondary towns and small peripheral municipalities. The INSEE definition of an urban unit is not appropriate because it is based solely on criteria of urban density and morphology. We therefore chose to apply the notion of urban area  used by INSEE for censuses from 1990 onwards and applied retrospectively back to the 1968 census by P. Julien in his thesis (2001). The arbitrary threshold used to define the urban area would exclude certain urban municipalities in the Paris region which function relatively independently of the Paris agglomeration, but which are also home to households working in the Paris agglomeration and to pioneers of periurbanization. For this reason, we included all urban areas and municipalities of more than 5,000 inhabitants in the region.
56The Paris metropolitan area expanded considerably between 1982 and 1999, however, and the survey samples do not fully cover the entire area, notably the rural municipalities of the urban periphery. The most restrictive geographical scope is that of the PDP survey, delimited by three large zones defined by the Paris region’s urban development institute (Institut d’aménagement et d’urbanisme de la région d’Île-de-France [IAURIF]): the Paris agglomeration, the new towns, and the small and medium-sized towns in the urban area with good public transport links. We introduced this criterion of accessibility or proximity to the transport networks to define a geographical scope common to all surveys that is meaningful for the construction of a universe based on a functional conception of the Paris agglomeration. Rather than using the IAURIF definition at the various census dates, we chose a more flexible method for defining the accessible municipalities via a reconstitution of the development of transport infrastructures over the 20th century, with ‘accessible’ municipalities being those served by an underground, RER, railway station (excluding high-speed TGV lines), or motorway at the time of the survey.
57The common geographical scope thus defined, called the ‘Paris agglomeration’, comprises the Paris urban unit as defined by INSEE, as well as the municipalities of the Paris metropolitan area, the other urban areas of the Paris region (Île-de-France), and the municipalities of more than 5,000 inhabitants served by transport infrastructures (underground, RER, railway, motorways, and major roads) under the criteria described above.
Contours of the Paris agglomeration at the time of the 3 surveys
Contours of the Paris agglomeration at the time of the 3 surveys
58The municipalities included in this scope are different at each survey date but correspond to a constant definition of a geographical area affected by urban sprawl. The respondents living outside this geographical scope are therefore excluded from our samples. For each survey, this almost exclusively concerns small, isolated rural municipalities (Figure A.1.)
59Using calibration on margins, the weightings applied to respondents were calculated based on harmonized INSEE data from the censuses of 1968 to 2013, extracted by birth cohort and interpolated for the survey dates on the common geographical scope.
HLMs (habitations à loyer modéré) are social housing units for low-income households managed by public or private bodies financed in part by public funding.
The law of 1 September 1948 aimed to lift the rent freeze by allowing owners to fix market rents on new properties. In fact, it prolonged the existence of numerous old, substandard dwellings whose tenants enjoyed security of tenure and paid very low rents.
In this article, ‘Paris’ and ‘Paris intra-muros’ refer to the city of Paris inside the péripherique (inner ring road).
Municipalities (communes) and arrondissements (administrative divisions of large cities) are the smallest spatial units for which retrospective information on place of residence is available.
Bus networks, which improve the accessibility of certain poorly served municipalities, were not included in this typology, mainly due to a lack of retrospective information (large numbers of lines, limited historical documentation). Inclusion of the bus network would only marginally affect the rankings of municipalities in terms of accessibility.
These include historical studies of the Paris underground, Wikipedia entries on railway stations, and WikiSara entries on roads.
Municipal infrastructure is assessed by controlling for edge effects with calculation of Euclidean distances between stations and the municipalities’ main urban centres.
There are five new towns: Cergy, Evry, Marne-la-Vallée, Saint-Quentin-en-Yvelines, and Sénart. They were first conceived in the 1965 urban development plan as a means to focus urban expansion around secondary centres between 20 and 40 km from Paris. They now have a total population of slightly above one million.
The method used to match accessibility categories and municipalities of residence in individual trajectories does not take account of distances between home and station at the submunicipal scale, or of any urban obstructions along the travel route.
This law marked a transition from support for construction, which had helped to finance the high-rise estates developments built in the 1950s, to support for individuals, which included subsidized loans for first-time buyers (prêt aidé à l’accession à la propriété) and rent assistance (aide personnalisée au logement).
We are interested in residential choices at the couple level, without reference to individual factors. It might be interesting to study the gender power relations in these choices across birth cohorts; women in the post-war generations, more often economically active their predecessors, seem to have more say in the residential choices of the couple (Ogg et al., 2012).
If the individual was in a higher-level occupation at the start of their career, being self-employed at the end of working life is treated as horizontal mobility within the upper-middle class.
The DDASS managed health, social, and medico-social care services. With responsibility for child protection from the mid-1960s to the mid-1980s, it placed vulnerable children in foster care or children’s homes.
Parisian boulevards that encircle the city.
Government schemes to increase the stock of rental properties though tax breaks for buy-tolet investors.
The RATP (Régie autonome des transports parisiens) runs the public transport system in Paris and its suburbs.
According to census data, the proportion of homeowning households in the Paris region rose from 32.5% to 42.9% between 1968 and 1990.
An ‘urban area’ or a ‘big urban area’ is a group of adjoining municipalities, without pockets of empty land, encompassing an urban centre (urban unit) providing at least 10,000 jobs and rural districts or urban units (urban periphery) in which at least 40% of the employed resident population works in the urban centre or in the municipalities attracted by this centre.
Source: INSEE, https://www.insee.fr/en/metadonnees/definition/c2070.