The article offers an analysis of the work process of one of the groups of the Grenelle Environnement, based on participant observation and interviews with members. After having discarded the functionalist (it would be a major innovation) and the critical (it is a mystification) interpretations, the author suggests a pragmatic perspective, following actors’ commitments and interactions, thus highlighting the indetermination of this consultation process. He also stresses the crucial role of the procedure imposed on the group, as well as the style of facilitation of the meetings. Thus, despite a clear initial framing of the discussions, the detailed analysis of the evolution of the proposals of the group shows it has progressively gained a form of autonomy by imposing certain priorities.