The contemporary urban conflicts demand the constitutional and urban law fields, in what concern to its developments on tutelage s range of the right to the city. The actual dissertation reflects about the dimension of people s involvement on the construction process, implementation and execution of master plans, taking as reference-case Paraty municipality, privileging the analysis of the Complementary Law of Paraty s Master Plan draft published by city hall in November 2010. Considering that people s involvement in municipal urban planning, as a sign of democracy and citizenship, presumes an environment endowed with transparency, advertising and openness to people s demands, the study verified that people s involvement, assuring the rightness of urban principle, enables the effectiveness of the master plan, in perspective of achieving the social functions of the city.