In order to understand the importance and nature of kinship in an urban context within the KASS project, we performed an ethnographical survey in a large building in Nanterre. It shows that, in correlation with public support and grounded on love, vertical ties are based on a sort of moral obligation, whereas horizontal ones are elective. Due to the specific history of this building, these ties are articulated by a strong network of neighbors. It will no longer be possible to assert that contemporary individualism and wage earning have erased intergenerational ties which share the urban modernity of France.