This research builds on the participatory exhibition Barvalo. Roms, Sinti, Manouches, Gitans, Voyageurs, presented in 2023 at the Museum of European and Mediterranean Civilisations (Mucem) in Marseille, France, to examine the theoretical and practical challenges of participation in contemporary museums. Through an action-research approach, the thesis investigates power dynamics, the historical and contemporary representation of Romani communities, and the processes involved in decolonising museum narratives. It explores how co-creation with so-called “source communities” can transform curatorial practices and foster more just, polyphonic, and inclusive narratives. By considering the exhibition itself as an object of research, this work proposes methodological tools to rethink the civic and critical role of cultural institutions in addressing inherited stereotypes and responding to contemporary public expectations.