Luxembourg and Germany maintain one of Europe’s most intriguing border arrangements, characterized by the shared management of the Moselle, Sauer, and Our rivers. This cooperative governance, known as the German-Luxembourgish condominium, places these rivers, along with their islands and certain bridges, under joint sovereignty. Originating from the Congress of Vienna in 1815, this unique system emerged when European powers were redrawing borders in the aftermath of the Napoleonic Wars.
The arrangements set forth at the Congress of Vienna, particularly Article 25 of the Final Act, established joint ownership over these rivers instead of separating them with a conventional median line. This agreement was solidified by treaties signed in Aachen in 1816 between Prussia and the Netherlands, which ruled Luxembourg at that time. As Luxembourg gained independence and Prussia evolved into part of the German Empire, the 19th-century agreements continued to underpin the modern German-Luxembourgish border, adhering closely to the historical delineation.
For over a century, the status of bridges crossing these shared rivers remained ambiguous. It wasn’t until discussions following the canalisation of the Moselle in 1979 that clarity began to emerge. A border treaty signed in 1984 officially included these bridges and footbridges within the shared territory, thereby resolving longstanding uncertainties.
Today, this condominium operates under a system of concurrent jurisdiction, allowing both German and Luxembourgish laws to apply. Bilateral agreements are in place to address potential conflicts. Law enforcement agencies from both nations can function within this shared region, even conducting joint patrols. When offenses occur on these shared rivers or bridges, officers from either country can intervene, with jurisdiction over subsequent legal proceedings determined by factors such as the individuals involved and the nature of the offense.
This arrangement stands as a rare instance of shared sovereignty within Europe, offering a distinct model of cross-border cooperation that differs from the conventional boundaries typically found between nations. It exemplifies a collaborative approach to border management, fostering a unique system where dual governance prevails.