The main objective of this paper is to propose a critical reflection of two political scientists involved in the organization of two deliberative mini-publics in Belgium: the G1000 and the G100. The first case was organized in 2011 at the country level, in a context of political crisis due to the absence of a federal government. It led to a large-scale project divided into three phases: an online consultation, a citizen summit on November 11, 2011 gathering more than 700 participants, and a citizen panel of 32 people. The second case was inspired by the former but was organized at the local level, in the municipality of Grez-Doiceau, and gathered 50 participants. In the two cases, the authors of this contribution were members of the organization group. After a brief description of the two mini-publics, this paper offers insights into the tensions between the position of the researcher and that of the activist. Firstly, we analyze the rationale and the motivations underlying this hybrid position between actors and researchers. Secondly, we discuss the potential impact of such a profile on the design of participatory and deliberative projects. In doing so, we also look at the interactions with the actors of these projects, and more specifically the private consultants. Finally, we reflect on the impact that this type of engagement has on research.