Luxembourg and Germany share a distinctive feature in Europe: a joint governance of the Moselle, Sauer, and Our rivers, which forms part of their border. This unique arrangement, known as the German-Luxembourgish condominium, is unlike conventional borders that typically draw a dividing line between nations. Instead, these rivers, along with their islands and certain bridges, fall under the joint sovereignty of both countries, a system that dates back to the Congress of Vienna in 1815. This congress, held after the Napoleonic Wars, was responsible for redrawing the borders of Europe.
The decision to place these rivers under joint ownership rather than dividing them through a median line was mandated by Article 25 of the Final Act of the Congress of Vienna. This arrangement was solidified by treaties signed in Aachen in 1816 between the Netherlands, which governed Luxembourg at the time, and Prussia. Although Luxembourg later gained independence and Prussia became a part of the German Empire, the agreements from the 19th century have continued to govern the modern border between Germany and Luxembourg.
For more than a century, the status of the bridges crossing these shared rivers was ambiguous. It wasn’t until after the canalisation of the Moselle that negotiations, beginning in 1979, sought to clarify this. In 1984, a border treaty was signed to officially include the bridges and footbridges within this shared territory, ensuring that both nations had a clear understanding of their shared responsibilities and rights.
Today, the condominium operates under a system of concurrent jurisdiction, where both German and Luxembourgish laws are applicable, and bilateral agreements help to resolve any potential conflicts. The police forces from both countries are empowered to operate within this shared area, conducting joint patrols and intervening in offences occurring on the rivers or bridges. The jurisdiction for legal proceedings depends on factors such as the individuals involved and the specific circumstances of the incident.
This shared sovereignty is a rare occurrence in Europe, presenting an atypical border arrangement that differs from the standard boundaries found between most nations. It stands as a testament to the cooperative relationship between Luxembourg and Germany, showcasing how historical agreements can continue to influence modern-day governance and international relations.