The existence of a rule protecting minorities does not necessarily imply that it is invested by the public authorities. The law identifies different motives of racism and discrimination, but how are they assumed by civil society, the political power and in the courts? A distinction must be made between the rule and the legitimacy of its use. The political recognition of social prejudice influences the behaviour of the actors involved in the prevention, manifestation, and repression of that prejudice. However, whether the word that designates it, the reality that it covers, the symbolic status of the victims, or the organizations that defend them, it appears that the Islamophobic phenomenon is considerably delegitimized in contemporary France. This article addresses this dialectic between legitimacy and legality through a series of questions concerning the production, mobilization, and implementation of anti-discrimination law when the presumed victims are Muslims.