International audienceThis paper makes three contributions: first, it analyses and conceptualizes professional shareholder activists and their use of international investor networks to engage French companies. We explain the changes in French legislation and corporate governance that facilitated the professionalization of shareholder activism. We then develop the conceptual model concerning the collaborative dimension of investor networks in France. Second, the paper determines the roles they play within the shareholder activism process in France. We document the functioning of shareholder activist actors that mobilize international investor networks. Finally, the third contribution is to illustrate the roles played by these professional actors and international investor networks in the shareholder activism process in France with two case examples