This research investigates the processes of adaptation of participatory budget (PB) institutions to France, Germany, and Great Britain in relation to frames of citizen participation, for instance ‘participatory’ democracy or ‘community empowerment’. I define frames as relatively coherent but flexible idea combinations that contain cognitive and normative assumptions about the issue at stake (in the present case citizen participation). The process of PB, developed in Porto Alegre, Brazil, includes ordinary citizens in the allocation of public funds and thereby breaks with a traditional approach to democracy. Various actors and actor networks have imported it into Europe since around 10 years, where it belongs to the most interesting participatory instruments. But how far-reaching are the results of PB in Europe? Central questions of the research, a comparative case study of three PB processes investigated with qualitative methods, concern the relation between frames of citizen participation and PB institutions, the degree of procedural and political innovation of PB, and the similarities and differences between frames of citizen participation in Germany, France, and Great Britain today. I argue that frames, of which the national and cross-country diffusion is strongly related to the activities of single policy entrepreneurs and networks, are never simply ‘put into practice’, but are adapted to the respective institutional setting and interpreted or re-interpreted in line with contextual features and the changing political interests and normative perspectives of the organising actors. Whereas new frames are in the beginning promoted by a small group of people, they might develop into more widely shared assumptions about the conduct of public policies, i.e. become a new référentiel of public policies. The three cases of PB analysed show distinct results in relation to the degree of innovation, which is influenced by different intervening factors (namely the frame of citizen participation, political and administrative support), as well as by the pace of the procedural development. Once implemented, a PB process may produce unexpected results, which in some cases become even more important than the initial goals. One hypothesis that emerges from this study is indeed that despite the political focus of many organisers, PB processes might contribute primarily to the introduction of a user-oriented administration rather than a ‘democratisation of democracy’. With regard to the frames of citizen participation in France, Germany, and Great Britain today, the current situation is characterised by more differences than similarities. Although all frames considered here share an overall criticism with regard to a ‘pure’ model of representative democracy, their particular focus differs (e.g. devolution of power to local citizens and communities without modifying the centres of power; participation in terms of top-down consultative devices or as a second, equally legitimate basis of democracy next to the vote for representatives). These differences, as well as diverse PB and other participatory practices, reflect different political traditions in Europe as well as distinct scenarios with regard to the future development of the democratic order.