This paper investigates determinants of farmers-members participation in collective platforms and their decision-making structures. The study uses the example of French innovative platforms for collective marketing, which scale-up local produce supply for new clients. Building on the literature on cooperatives, we identify several explanatory factors. Using a probit regression, we find affective motivations prevail over economic reasons to become a member, while other principal factors included investments in human resources and background of farm business. Rentability and trust in governing bodies are principal motives to join decision-making structures. We discuss trough what mechanisms potential participation in platforms emerge.