Much public participation research is built on the assumption that participatory arrangements empower citizens and disrupt existing power structures. This article challenges that claim. Drawing on one participatory venue considered most likely to empower citizens in Basel, Switzerland, the study shows that meaningful collective power has been conferred to citizens. However, resourceful and organisationally privileged actors have influenced the impact of citizen’s demands on public decision-making in significant ways. The study concludes that the production and implementation of collective power deriving from citizens depends on distributive power sources residing in governments and bureaucracies. As a result, participatory arrangements that aim to direct state action have to conform to some extent to the rules and structures underlying ordinary policy-making. The case study highlights the intertwined relationship of the ‘power to’ and the ‘power over’ and shows how the interplay between these two forms of power places conditions on the empowering potential of participatory arrangements.