Law has been considered in the approach of economics and sociology of conventions (EC/SC) as a tool enabling the actors to consolidate the regularity they aim for in their coordination. A first part presents the specific perspective on law that EC/SC develops, renewing institutionalist approaches in economics and sociology. It underlines the distinction between legal rules and behaviors, and suggests a conception of law as a frame for collective actions. A second part analyzes the place of law in economics and sociology of conventions as it emerges in the first works of this approach, and evokes the conception of law as an investment in form. A third part considers court action as a possible break in the continuity of conventions, from a "regime of adjusted actions" to a "regime of dispute in justice". The fourth part sheds light on the historical dynamics of law, using the example of labor law in a perspective of several "worlds of law". The fifth part presents the critical character of recent research, in face of the neoliberal de-institutionalization.