This paper analyzes how French cooperative banking groups adapted their organization, status and model to develop and grow, until the current financial crisis. It explores how they benefitted from evolutions in cooperative law that lowered financing constraints and increased the scope of their activities, becoming large banking groups, and identifies how these groups tried to develop a model of governance, characterized by internal control, which was partly dedicated to the members, but biased more and more towards the top of the organizational pyramid and to stockholders (the new stakeholders coming from the existence of listed vehicles). While the developing business model for cooperative banks appeared to confer a comparative advantage and was synonymous with efficiency before the financial crisis, it seems that the hybridization of the cooperative model has also been a source of conflict of interest, weakness in strategy and an incentive to increase risk. The third part