In addition to the findings on the crisis of representative government, which emphasizes the mistrust of citizens, the climate crisis is seen as revealing the impotence of this political form based on elections. In the academic, activist and political arenas, voices speak in favor of the use of mini-publics drawn at random to solve various political issues, in particular climate change. While citizen assemblies on climate have recently multiplied, it is worth examining their precursor: the Irish Citizens' Assembly (ICA). While this deliberative mechanism has suggested the legalization of abortion in 2017, approved by referendum, it has also dealt with climate change. Through an extensive field study, the ICA's climate deliberations are analyzed, in particular the tension between the power of participating citizens and control by organizers and experts. The Irish case will then be compared to the French Citizen Climate Convention, which was also the subject of a full field study.