This dissertation intends to reflect on the contemporary debate concerning the fundamental rights to housing and to environment. The aforementioned rights, conflicting in the discourses of both the academia and the laymen, conduct us to question the possibilities and barriers to the right to the city. The rapid growth of urban areas, the generalized poverty and the absence of public policies have, among other factors, made impracticable for many inhabitants to live in a worthy housing, with the adequate infra-structure and the required documentation. They end up moving to restricted places, often environmental preservation areas. In a quest to understand such a complex subject, this work privileges the reach of the right to the city, a human right, considered a beam of constitutionally granted rights. Given the social function of the city - in accordance with the institutional landmarks brought by the Federal Constitution, the City Statute and the Zoning Regulations of the municipalities - the matter was developed from the standpoint of the environment preservation and the popular housing issue. In the scope of the constitutional order and the urban law, this study goal was to equate the theoretical and methodological challenges posed by the social effectiveness of the norm. Using the dialogue of sources method, it was able to identify equilibrium between the two fundamental rights, complementary and compatible, because necessary to the complete realization of the right to the city. The course of the new interpretation to the referenced conflict counted on extensive doctrinal, legal and jurisprudential research, including state-of-the-art literature on the field, besides the analysis of Courts of Appeal rulings from the states of Rio de Janeiro and São Paulo.