In France, the emerging wave of citizen renewable energy projects is in line with the European vision and national policies aimed ata more sustainable energy transition. The rise of these initiatives in France, is inspired in part by the successes observed in Germany (Fontaine, 2019) and other European countries (Poize and Rüdinger, 2014).  Scientific research on energy communities and the spatial diffusion of citizen renewable energy (RE) projects has grownsignificantly in recent years, reflecting the growing interest in decentralized,participatory energy solutions (Rüdinger, 2019; Gomez and Tyl, 2023). Our studybuilds on previous work identifying Western France as a fertile ground for RE initiatives dueto its historical commitment to sustainable development(Sebi and Vernay, 2020). The aim of this study is to present the process of spatial diffusion of renewable energy initiatives in Western France. From this perspective, our work examines how citizen renewable energy projects are deployed and spatially diffused in Western France. Which local players are involved in this participatory/community energy dynamic, and how do they interact ? How do territorial, social and environmentals pecificities influence these diffusion processes ? What is the role of support networks, notably RECIT and TARANIS, in implementing and supporting these initiatives? Our findings are based on database analysis combined with a quantitative study of data provided by RECIT, TARANIS and Energie Partagée, qualitative data from a corpus of individual interviews conducted in Bretagne and Pays de la Loire, and the practice of participant observation through immersion in developing citizen collectives.