Ethnic categories have only come to be used gradually in sociology in France, and debate on the issue has been quite heated, primarily because such categories are extremely remote from French intellectual tradition. However, they have gained scientific legitimacy by their clear sociological relevance, though the matter of how to define and develop them empirically remains uncertain and complex. In his overview of the debate, Georges Felouzis probes the role of ethnic categories in French sociology from both theoretical and empirical standpoints. Dominique Schnapper takes up what is at issue and at stake for democracy and society in the use of ethnic categories, and Patrick Simon reflects on possible ways of describing and accounting for “ethnic” social relations in French society.