The objective of the study is to analyze the functioning of four participatory initiatives implemented as part of health studies conducted by the Health and Environment Directorate of Santé publique France (the former Kodak site in Vincennes, the Mineral and Raw Materials Center in Aulnay-sous-Bois, the Bourdenières Elementary School in Chenôve, and the Aube Storage Facility in Soulaines). It aims to assess the benefits, challenges, and limitations of involving local stakeholders in addressing local environmental health concerns. Semi-structured interviews were conducted with selected participants from the monitoring committees of these four studies, and participant observation was carried out within the Soulaines committee. The study demonstrates the value of these forums for exchange. They facilitate: the expression of expectations, points of disagreement, or misunderstandings; the questioning of obtained results; the improvement of the quality of scientific results through the integration of local knowledge; and, at times, greater acceptance of management options. The difficulties encountered relate to perceptions of the roles assigned to stakeholders, communication issues during the consultation process or when presenting results, as well as persistent disagreements regarding certain directions of the expert analysis. The outcome of the process does not depend solely on the composition of the committees but rather on a combination of multiple factors. Finally, the study highlights that better framing of the consultation process in advance, through a contractual document, would likely improve communication among stakeholders.