The border shared by Luxembourg and Germany is one of Europe’s most unique, defined not by a straight line but by the joint governance of the Moselle, Sauer, and Our rivers. This unusual arrangement, known as the German-Luxembourgish condominium, places these rivers, their islands, and certain bridges under the joint sovereignty of both countries. This system has its roots in the Congress of Vienna of 1815, where European powers redrew their borders in the aftermath of the Napoleonic Wars.
According to Article 25 of the Final Act from the Congress of Vienna, rather than being divided traditionally, the rivers became a shared possession. This agreement was reinforced by treaties signed in Aachen in 1816 between the Netherlands, which governed Luxembourg at the time, and Prussia. Even as Luxembourg gained independence and Prussia became part of the German Empire, the rights established in the 19th century continued to hold sway, shaping the modern border that exists today.
The status of the bridges spanning these shared rivers was ambiguous for over a century. It wasn’t until after the Moselle river was canalised that negotiations took place, beginning in 1979, to address the issue. A significant development came in 1984 with a border treaty that clarified the status by including bridges and footbridges within the shared territory.
This rare example of shared sovereignty in Europe operates under a system of concurrent jurisdiction, meaning that both German and Luxembourgish laws can apply. Bilateral agreements are instrumental in resolving potential conflicts that arise. Police forces from both countries have the authority to operate within this shared territory, conducting joint patrols and intervening in incidents that occur on the rivers or bridges. The jurisdiction for legal proceedings depends on various factors, including the individuals involved and the circumstances of the incident.
The German-Luxembourgish condominium remains an exceptional case of shared governance, distinguishing itself from the conventional borders found between most nations. This arrangement not only highlights a historical legacy but also exemplifies how two countries can maintain a cooperative and shared approach to border management.