The communication's case study deals with the trajectories of Brazilian family farmers of Aguas Emendadas territory (Federal District) in participative procedures and the effects of this participation device proposed by Agrarian Development Ministry among the PDSTR (Sustainable Development Program of Rural territories). The social and political resources distribute very unevenly the chances of family farmers to integrate and stay in participation procedures. The legitimacy of the participants of the rural "civil society" is based on three main elements: their capacity to represent farmers' communities; their institutional activism: negotiations and formalization with public administration technicians and officials in order to select "good" policy projects; the dominion of the expertise. However, we observe the appearance of sector-based "elite of the participation" among family farmer. To conclude, this participative policy making constitutes an hybridization between several models of public action and between several political practices of participation.