The Union eco-neighborhood pilot project, in the Urban Community of Lille, France, has set up an ambitious process of participative negotiation that has drawn our interest, becoming the basis of this analysis. Various devices and spaces for dialogue have been created to allow interaction between different actors, and although the impact on decision making is slow, this project can be seen as a good example in the area of participative management. The main objective of this paper is to show some relevant results of the research on participative process to develop and implement the Union eco-neighborhood, with the intention of opening our vision to other contexts and experiences which also seek to develop more democratic forms in urban projects. The research uses qualitative and empirical methods based on interviews with key stakeholders, observations of various dynamics (such as public meetings about the project) and local and international literature review in this domain.