Context: The organization of primary care in France has long remained a secondary issue on the political agenda. The government began to address the difficulties of care access and coordination in the 2000s, when a seemingly viable solution emerged from the field: the maisons de santé pluriprofessionnelles (MSPs). In a corporatist system and a predominantly private sector, the government chose an incentive-based contractual policy to encourage providers to join these structures. This article analyzes the implementation of this policy, which depends on private providers’ commitment. Methods: The article offers a comparative case study of six MSPs. Data were collected through semistructured interviews, observation sessions, and document analysis. Findings: First, the article shows that the emergence of MSPs has only been possible thanks to an unprecedented alliance between general practitioners, the state, and the health insurance fund. Second, it argues that MSP policy implementation relies on a complex bargaining process between private providers and public authorities that enables the former to shape it to their local needs. Conclusions: MSP implementation experiences raise questions both about the understanding of medical corporatism in France and the assimilation of policy changes and local variation through policy implementation.