Luxembourg and Germany share a distinctive boundary in Europe, characterized by the joint governance of the Moselle, Sauer, and Our rivers, rather than being delineated by a traditional border line. This arrangement, known as the German-Luxembourgish condominium, involves shared sovereignty over the rivers, their islands, and certain bridges. Originating from the Congress of Vienna in 1815, this system was established when European powers redrew their borders following the Napoleonic Wars.
Article 25 of the Final Act of the Congress of Vienna established the joint ownership of these rivers, opting for shared governance instead of a median division. This setup was reinforced by 1816 treaties signed in Aachen between the Netherlands, which then governed Luxembourg, and Prussia. Even after Luxembourg gained independence and Prussia became part of the German Empire, the rights agreed upon in these 19th-century treaties persisted. Today’s German-Luxembourgish border largely reflects the framework created in that historical context.
For over a century, the status of bridges spanning the shared rivers was not clearly defined. It wasn’t until the canalisation of the Moselle prompted negotiations in 1979 that the matter was addressed. A border treaty finalized in 1984 clarified the inclusion of bridges and footbridges within this shared territory. This unique border is managed through a system of concurrent jurisdiction where both German and Luxembourgish laws apply, aided by bilateral agreements to navigate potential conflicts.
The rare example of shared sovereignty allows police forces from both countries to operate within the condominium, including conducting joint patrols. Officers from either nation can intervene when an incident occurs on a shared river or bridge. Subsequent legal jurisdiction depends on various factors, including the individuals involved and the specific circumstances of the incident.
The German-Luxembourgish condominium remains a notable instance of shared governance in Europe, functioning differently from conventional national boundaries. This unusual arrangement underscores an ongoing collaboration that reflects the historic agreements and modern legal frameworks sustaining the joint management of these waterways.