This study aims to analyze the importance and impact of civil society participation in governance of the metropolitan region of Rio de Janeiro. For this we analyzed the Reconstruction-Rio, a project of integrated urban intervention, developed over ten years in eleven municipalities in the metropolitan region of Rio de Janeiro. It is suggested that the practice of citizenship depends on the activation of the public sphere, a form of mediation between state institutions and community interests. And it also suggests that this practice is essential for both the legitimacy of government action, and for the establishment of a democratic political culture. The role of citizen participation in the democratization of the public sphere was reconstructed analytically based on studies of Habermas, Fraser, and Nuria Grau (1988). Special attention was given to the study of social movements, considered critical to increasing participation in the governance of the analyzed project. Finally, collaborative planning was considered a critical tool to increase the participation and democratization of the state sphere.