Federal states like Belgium operate under conflicting pressures in the conduct of their international relations: centralizing pressures, on the one hand, imposed by the necessity of speaking with a single voice in order to forge a coherent international policy and decentralizing pressures, on the other, because globalization stimulates a qualitative and quantitative extension of the internal and international roles of substate players, mainly through the international deployment of substate paradiplomacy. This centralization of external affairs and the centrifugal forces introduced by globalization cause problems in this type of system, in which substate entities have numerous fields of jurisdiction. This new phenomenon is not without its risks because it leads to disorder and conflict. In many countries, the development of paradiplomacy by the substate actors creates conflict with the central government. The impression is created that the federal and the substate authorities are condemned to fight a zero-sum struggle for access to the international system, the former seeking to prevent the latter from playing a role in the development of foreign policy and to limit all international action by them. The case of Belgium is of particular interest since its substate entities are the most dynamic regions in the world in international relations. The objective of this article is to evaluate the impact of the Flemish identity paradiplomacy on the foreign policy of the federal state.