Interdisciplinarity has become a buzzword in the academic world. Promoted by actors holding often very different conceptions, the notion has become both central in academia and covers highly divergent practices. This article examines how the goal has effectively been pursued in Genèses, a French social science journal established in 1990 in order to foster interdisciplinary exchanges. Based on bibliometric methods, the paper studies the everyday practice of interdisciplinary exchanges. Three levels of analysis are proposed in turn : first, the interconnections between French social scientific publications ; second the authors of Genèses, whose properties have significantly evolved since its creation and third the references that are mobilized within the articles, that offer a glimpse into other, more subtle forms of disciplinary hybridization. From this specific but telling vantage point the article reveals a surprising decline in the practice of interdisciplinarity in the French social sciences over the last two decades.