This PHD aims at documenting the spatial mobility practices of the teenagers who live in segregated neighbourhoods, so as to promote an understanding of life in such places and to explore potential desegregation effects of increased mobility. This issue is addressed here through the case of the "Zones urbaines sensibles" (ZUS) in the Parisian region, mainly the “cités” as coined by the French. So as to understand what distinguishes the teenagers who live in ZUS from the others, so as to understand also what divides them, we have chosen to apprehend them under the double angle of their district and social background. That double angle allows to take into account the social socio-spatial distinctions within the ZUS but also to question the th...