Luxembourg and Germany are connected by one of Europe’s most distinctive border arrangements, where the Moselle, Sauer, and Our rivers are not separated by a traditional boundary line but are instead jointly governed. This unique setup, known as the German-Luxembourgish condominium, grants both countries shared sovereignty over the rivers, their islands, and certain bridges. This arrangement traces back to the Congress of Vienna in 1815, where European powers redefined borders after the Napoleonic Wars.
According to Article 25 of the Final Act of the Congress of Vienna, it was decided that these rivers would be under joint ownership rather than being split along a median line. This decision was reaffirmed in 1816 through treaties signed in Aachen between the Netherlands, which governed Luxembourg at the time, and Prussia. As history progressed, Luxembourg gained independence, and Prussia became part of the German Empire, yet the rights under these 19th-century agreements persisted, shaping the modern border as it exists today.
The status of the bridges crossing these jointly governed rivers remained ambiguous for over a century. However, the canalization of the Moselle prompted negotiations in 1979 to address this issue. These discussions culminated in a border treaty signed in 1984, which officially incorporated bridges and footbridges into the shared territory. This treaty further solidified the cooperative nature of the region’s border management.
Today, the condominium operates under a system of concurrent jurisdiction, allowing both German and Luxembourgish laws to apply within the shared territory. Bilateral agreements are in place to resolve any potential legal conflicts that may arise. In practice, police forces from both nations can operate in the area, conducting joint patrols and responding to incidents. When an offence occurs on a shared river or bridge, the jurisdiction for legal proceedings is determined by factors such as the individuals involved and the circumstances surrounding the offence.
This arrangement continues to be a rare example of shared sovereignty in Europe, offering a distinctive approach to border governance that differs from the conventional boundaries seen between most countries. The German-Luxembourgish condominium stands as a testament to international cooperation and the enduring legacy of historical treaties in shaping modern territorial agreements.