Competition policy is one of the few truly integrated policy fields of the European Union (EU), with supranational actors like the European Commission having extensive competences. Scholars consider it to be a relatively stable policy domain, characterised by strong path dependencies, a solid anchoring in European primary law, and the pre-eminence of epistemic authority. However, in recent years, EU competition policy has undergone remarkable changes including merger control, projects of common European interest, and state aid. This article argues that France and Germany, the EU’s two largest member states with most financial resources, have been decisive in promoting and realising these changes. Competition policy is an unlikely case for Franco-German European-level political work, primarily because of the supranational character of the policy field and the two countries’ oftentimes opposing positions on aspects related to the European single market. Building on policy document analysis and expert interviews, the article shows how and why France and Germany, partly in confrontation and partly in alignment with the Commission, have re-shaped EU competition policy.