Can participation contribute to a modernisation of public services? Even if the idea of modernisation is only implicit in the Porto Alegre experiment, it constitutes an explicit aim of many participatory budgets in Europe. In contrast to a model where public service modernisation is mainly based on privatisations, we explain the idea of a ‘participative modernisation’. The first section shows the general strategy of this approach that aims at integrating laypersons’ competencies in public administrations work. The second section discusses different roles for laypersons’ inclusion linked to possible benefits and obstacles. The last section is about technical democracy, which gives a broader theoretical foundation to citizen participation in public administration.