The border between Luxembourg and Germany is one of Europe’s most intriguing, defined not by a solid line, but by the shared governance of the Moselle, Sauer, and Our rivers. This unique arrangement, known as the German-Luxembourgish condominium, places the rivers, their islands, and some bridges under the joint sovereignty of both nations. This system was established during the Congress of Vienna in 1815 when borders were redrawn in the aftermath of the Napoleonic Wars.
Article 25 of the Congress of Vienna’s Final Act laid the groundwork for this shared ownership, opting against a traditional median line division. The unique arrangement was further solidified by treaties signed in Aachen in 1816 between the Netherlands, which then controlled Luxembourg, and Prussia. Despite Luxembourg’s subsequent independence and Prussia’s incorporation into the German Empire, the 19th-century agreements’ rights have persisted, shaping the modern German-Luxembourgish border.
For over a century, the precise status of the bridges spanning these shared rivers remained ambiguous. It wasn’t until 1979, after the Moselle’s canalisation, that negotiations began to resolve this ambiguity. The issue was finally addressed in a 1984 border treaty that officially included bridges and footbridges within the shared territory. Today, the condominium is managed by a system of concurrent jurisdiction, allowing both German and Luxembourgish laws to apply, with bilateral agreements guiding the resolution of any potential conflicts.
Law enforcement in the shared territory operates under this cooperative framework as well. Police from both countries are authorized to conduct joint patrols and intervene when offenses occur on the rivers or bridges. The jurisdiction over subsequent legal proceedings can vary based on factors such as the individuals involved and the specific circumstances of the offense. This system remains a rare instance of shared sovereignty in Europe, presenting a distinct alternative to the typical national boundaries.