The border shared by Luxembourg and Germany is one of Europe’s distinctive geographical features, defined not by a traditional line but by jointly governed rivers. This unique arrangement, known as the German-Luxembourgish condominium, includes the Moselle, Sauer, and Our rivers, as well as their islands and specific bridges. This unusual system traces its origins back to the Congress of Vienna in 1815, which redrew borders across Europe in the aftermath of the Napoleonic Wars.
Article 25 of the Final Act of the Congress of Vienna established that these rivers would be under joint ownership instead of following a conventional median line. This arrangement was further solidified by treaties signed in Aachen in 1816 between the Netherlands, which then governed Luxembourg, and Prussia. As political landscapes changed with Luxembourg’s independence and Prussia’s integration into the German Empire, the agreements held firm, and the modern border continues to reflect this historical accord.
For more than a century, the status of bridges crossing these shared rivers was ambiguous. It wasn’t until the canalisation of the Moselle that serious negotiations began in 1979 to address the issue. Subsequently, a border treaty was signed in 1984, officially incorporating bridges and footbridges into the shared territory under the condominium.
Governance of this shared space is managed through concurrent jurisdiction, where both German and Luxembourgish laws are applicable. Bilateral agreements are in place to resolve potential conflicts. Law enforcement from both countries is authorized to operate within the shared territory, including conducting joint patrols. When an offence occurs on the shared rivers or bridges, officers from either nation can intervene, with legal jurisdiction in subsequent proceedings determined by factors like the involved parties and the circumstances of the offence.
This German-Luxembourgish condominium remains a rare instance of shared sovereignty in Europe, making it a unique border arrangement that deviates from the conventional demarcations seen between most countries.