This paper reviews the evolution of alliances between advocacy groups and associations, on the one hand, and scientific institutes and agencies, on the other, in the field of environmental health in France from 1990 until now. The article describes how these public institutions of expertise have adapted to a new context, placing their collaborations with associations at the heart of their institutional agendas. By retracing the history of opening policies to society, we show the stakes, the different groups of actors involved, as well as the norms and procedures by which science reaches out to society. Finally, we highlight the main limitations of these policies and outline opportunities for associations and expertise organizations to continue this change.