At the beginning of the 1990s a new discourse emerged at the European Union level, insisting on the necessity of 'civil society' participation in decision-making processes. Based on a 'strategic-constructivist' research design, this article addresses the question of the emergence of this participatory turn in the official discourse and its transformation into a norm. It argues that the continued activism of an elite forum, consisting of political and administrative actors as well as academics, created the momentum that brought the concerned actors to accept the participatory norm and to play the roles required by it. However, due to internal competition amongst norm entrepreneurs, and a changed political situation, this norm is still contested, making it difficult to assess how its implementation will function.