The study was made in coordination with a laboratory of research (LOUEST-CNRS-Paris 8 University), and the task consisted in the description and analysis of the system that manage the demand for social housing. The aim was better to understand why the demand, as it is registered, and the allocation of social housing only imperfectly reflect the needs of the population. The main question was: how can the system meet the needs of the most disadvantaged sections of the population?