The border shared by Luxembourg and Germany is one of the most distinctive in Europe, characterized by the joint governance of the Moselle, Sauer, and Our rivers. This unique arrangement, known as the German-Luxembourgish condominium, means that these rivers, the islands within them, and certain bridges fall under the joint sovereignty of both nations. This system was established as far back as 1815 during the Congress of Vienna, when European borders were redrawn in the aftermath of the Napoleonic Wars.
Article 25 of the Final Act of the Congress of Vienna initiated the shared ownership of the rivers, diverging from the typical practice of dividing waterways along a median line. The arrangement was solidified by treaties signed in Aachen in 1816 between the Netherlands—Luxembourg’s ruling power at the time—and Prussia. As history unfolded, Luxembourg gained independence and Prussia became part of the German Empire, but the rights set forth in the 19th-century agreements persisted, shaping the modern border between Germany and Luxembourg.
The matter of bridges spanning these shared rivers remained unresolved for more than a century. However, after the canalisation of the Moselle, discussions began in 1979 to address this issue. These negotiations culminated in a border treaty signed in 1984, which formally included bridges and footbridges in the shared territory, thereby clarifying their status.
In today’s arrangement, the condominium operates under a concurrent jurisdiction framework. This means that both German and Luxembourgish laws are applicable within the shared area, and bilateral agreements help navigate any potential legal conflicts. Police forces from both countries have the authority to operate in these territories, conducting joint patrols and responding to incidents on the shared rivers or bridges. Jurisdiction over legal proceedings that follow such incidents is determined by factors like the individuals involved and the context of the offence.
This shared sovereignty model remains a rare occurrence in Europe, offering an intriguing example of how borders can be managed differently. It stands in contrast to the conventional boundaries that define most national borders, highlighting a collaborative approach to territorial governance.