Résumé : The discussion about comparison points out the limits of comparative frames, of problems of (in)commensurability, and reveals the transformations of categories circulating between national, global, or local realities (cf. Amelina and Faist, 2012; Reuter and Villa, 2010; Wimmer and Glick Schiller, 2002). In this regard it leads inter alia to the question of the critical asset unfolded by the comparative approach in social sciences research. [premières lignes]