Based on extensive new empirical fieldwork (via a case study of the reform of the territorial State in 2007–2010), this article interrogates the meaning of the prefectoral institution in France. The central puzzle this article addresses is the survival of a pre-democratic institution – the Prefect in – a democratic, decentralizing and Europeanised Republic. Changing conditions have required institutional resilience and adaptation in a period of state restructuring and rescaling. The case study of the prefectures as old institutions is framed using language and tools of new institutionalism across three dimensions: the timing and sequence of decision-making, the logic of appropriateness, and interaction. Beyond the narrow case of the prefectures in France, the article makes the case for combining modes of institutionalist analysis in order to penetrate generalities about the black box of institutions.