The objective of this analysis is linked to the discussion of urban residential segregation marked by the Brazilian urban land structure and perpetuated by urban planning instruments at the municipal level. The spatial focus of the study is the municipality of Londrina (state of Paraná/Brazil). We aimed to analyze the relationship between urban zoning and the dynamics of residential segregation, unfolding two foci: verify to what extent the objectives presented in the municipal instrument translate the objectives of the instrument at the federal level (the City Statute–CE) and the national program “My Home, My Life” aimed to provide housing to socially vulnerable populations; the second focus, aims to assess how the planning instrument—the Special Zone of Social Interest (ZEIS), contemplated in the Land Use and Occupation Law and in the Municipal Master Plan of Londrina (PDPML, 2008)—materializes in practice the objectives of promoting equity in access to housing. The results show that although the objectives defined at the federal level are transposed to the municipal level, demonstrating a theoretical coherence between the instruments, there are flaws in their implementation. The case study results show that the urban zoning of Londrina has as a guideline a segregationist territorial ordering, leading to a residential segregation of the population with low purchasing power. On the other hand, the planning instrument that could change this reality is the ZEIS that, on the contrary, reinforced social housing in the periphery, conditioning the right to the city and perpetuating the social vulnerability of disadvantaged groups, in a process common to other Brazilian cities. Such constraints make relevant the establishment of land reserves for social housing based on clear roles of a social and functional mix, reinforced by the combat of vacant spaces and the definition of minimal housing and infrastructure densities to allow urban occupation.