In the 2000’s, both French and German unions have advocated for the measuring of quality of working life. A national interprofessional agreement recognized “qualité de vie au travail”, quality of working life, as a category of collective bargaining in France in 2013. In Germany, the German Trade Union Confederation has been producing an index on “good work” (gute Arbeit) based on ad hoc employee surveys already since 2007. Do “qualité de vie au travail” and “gute Arbeit” cover the same realities, the same issues? Beyond the similarities that emerge at first glance, we show that these two categories differ both in terms of the paradigms that underlie them (a social problem on the German side, a public health problem on the French side) and of the ways scientific expertise is mobilized in the categorization process.