Presentation for the Panel ``Panel Fieldwork in Political Science 2. Reflections on Ethnographic Methods'' APSA 2020 Virtual Annual Meeting Social movement literature shows that since the 1960s mobilization entrepreneurs have mainly originated from the middle and salaried classes, with strong cultural capital and previous politicization. However, recent mass protests such as the Yellow Vests movement in France have been characterized by unprecedented proportions of members of the working class and of destabilized middle classes, residents of suburban areas, who most often happened to be first-time protestors. These unexpected, inexperienced activists raise a conundrum for scholars of social movements and political participation alike, all the more so as they largely contribute to renewing the social movement repertoire as well as conceptions of citizenship. In order to account for first-time protestors' crucial commitment, we build a case for a very qualitative method, namely ethnographic biographical interviews.