The author provides an analytical model to capture mechanisms of supranational impact on national public administrations. The aim is to understand how we can perceive a European administrative space given the persistent diversity between member states. In face of the overly complex subject matter, it is argued that a typology that presents ideal types of interaction modes between supranational and national levels of administration provides in fact a suitable pragmatic approach to understand the potential impact of European integration on national civil services. Scrutinizing which mechanisms of possible influence-taking the European Union (EU) invokes shows that administrative integration does actually not suggest overall convergence. Instead the shared administrative space works precisely because it preserves state-sensitive diversity. Only in the context of enlargement did the EU need to present a single model to the candidate states and thus the notion of an ever more converging single administrative space was invented. Despite the external promotion of a single model, the driving dynamic of the emerging European administrative space remains increased cooperation and common administration that respects and sustains differences between independent national public administrations. The theoretical framework and empirical application therefore provide a first step for further research to tackle how supranational integration changes national public administration.