The law on “local democracy” adopted in February 2002 imposes in Paris the creation of participative subdivisions within the territories of municipalities (arrondissements). The genesis, production and use of these new territories present questions for socio-political geography, notably in the complex context of Paris. One of these questions is the social criteria used in building sustainable political subdivisions. Despite of the famous social mixity notion, the elects have to choose concretely their subdivisions. They sometimes build social homogeneous neighborhood districts and potentially a territorial segregation which would underline and increase social disparities. In case of several municipalities, we propose to study elects’ speeches about this social and territorial question, then the really applied choices of subdivisions, and at last, the effects of those strategies on local participation and public action.