This work aims to link up two French approaches to economic phenomena on the question of institutional dynamics: the "économie des conventions" and the "theorie de la régulation". First, I examine and sum up each theory. Both agree on the decisive role played by politics in the process of elaborating and changing rules. However, they clearly go against each other about the format and the content of these political arbitrations. Secondly, I elaborate a synthesis. I put forward a common theory of convention which accounts for an agent simultaneously following and changing the rules. This theory of action is used to elaborate a general model of coordination explaining the dynamics of institutions.
