Luxembourg and Germany manage one of Europe’s most distinctive borders, where the Moselle, Sauer, and Our rivers are jointly overseen by the two nations rather than being split by a conventional boundary. Known as the German-Luxembourgish condominium, this arrangement places the rivers, their islands, and certain bridges under joint sovereignty. This unique setup dates back to the Congress of Vienna in 1815, when European powers redefined borders after the Napoleonic Wars.
According to Article 25 of the Final Act of the Congress of Vienna, the rivers were put under shared ownership instead of being divided by a typical median line. This arrangement was reinforced by treaties signed in Aachen in 1816 between the Netherlands, which then controlled Luxembourg, and Prussia. As Luxembourg eventually gained independence and Prussia became part of the German Empire, the rights established under these 19th-century agreements remained in effect, and the current German-Luxembourgish border reflects the arrangement set during that period.
For over a century, the status of bridges spanning the shared rivers was uncertain. Following the canalisation of the Moselle, discussions began in 1979 to address the issue. In 1984, a border treaty was signed that officially included bridges and footbridges within the shared territory. Today, the condominium is managed through a system of concurrent jurisdiction, allowing both German and Luxembourgish laws to apply, with bilateral agreements in place to resolve potential conflicts.
Law enforcement from both countries is active within this shared area, conducting joint patrols and operating under a cooperative framework. Officers from either nation are authorized to act when an offense occurs on a shared river or bridge, and the jurisdiction for any subsequent legal proceedings can depend on factors such as the individuals involved and the specific circumstances of the incident.
This rare example of shared sovereignty in Europe creates a border that functions differently from the conventional boundaries found between most countries. The German-Luxembourgish condominium continues to exemplify a unique approach to border management, maintaining a system of cooperation and joint governance that has endured for over two centuries.