This article analyses how state law promotes spatial segregation and how the system of rights operates in the segregated territory. The chosen field of study is the favelas of the city of Rio de Janeiro in Brazil. Even if some favelas are more than 100 years old, illegality and precariousness — temporal and material — are still considered as constituent attributes of favelas. The denial of recognition of this zone manifests itself even to the individual who resides there: his life is not validated or is validated with constraints. It is therefore a depreciative and depreciated space capable of highlighting the limited and boundary category of citizenship. The confrontation between legal norms and the interstitial system of rights in the favelas makes it possible to observe that the law is not interested in the needs of these persons (omission) but that it operates in an institutional process of exclusion of residents from the favelas (action). In other words, the law is a key element for the construction and perpetuation of marginalization, including with regard to the physical space of these citizens.