Numerous projects, which today are described as social innovations, are being developed in response to the recent crises to meet various unsatisfied social needs (housing, climate, ageing, inequalities, etc.). Their highly collective nature implies a better understanding of the ways in which the partners involved in these projects are connected, which we propose to do using the relational chain method. The data collected using this method highlights the significant use of non-personal arrangements (circles and calls for projects) to obtain the support of institutions (local authorities) or organisations (foundations); interpersonal relationships—essentially professional—appear to be mobilised less frequently and mainly to access the world of research.