This article examines why the activism of the children of North African immigrants has not been noticed or recognized by elected officials of the Communist Party. Through historical and ethnographic study of a Communist municipality in the greater Paris region, the article first demonstrates that this militancy, far from being a new thing, is inscribed in the traditional forms of the militancy associated with the "banlieues rouges." In order to understand the urban activists' invisibility in politics, the author analyzes the negative representations of the group from which they come and the tensions between North African immigrants and local officials of the Left, tensions linked to urban renewal in the industrial suburbs. The detour through the history of the "red suburbs" thus reveals the structure of the tense relations between the Left and the housing projects, which seem to be disowned not only economically but also politically.