Luxembourg and Germany are connected by a unique geographical feature in Europe, where the Moselle, Sauer, and Our rivers are collectively governed rather than being separated by a typical border. This arrangement, known as the German-Luxembourgish condominium, establishes joint sovereignty over the rivers, their islands, and certain bridges. This unusual system originates from the Congress of Vienna in 1815, which redrew European boundaries after the Napoleonic Wars. Instead of dividing these waterways along a conventional median line, Article 25 of the Final Act of the Congress placed them under shared ownership.
The agreement was initially confirmed by treaties signed in Aachen in 1816 between the Netherlands, then ruling over Luxembourg, and Prussia. As Luxembourg gained independence and Prussia became part of the German Empire, the provisions of these 19th-century agreements persisted, shaping the modern German-Luxembourgish border. It wasn’t until much later that the status of bridges crossing these shared rivers was clarified. After the canalisation of the Moselle, negotiations in 1979 aimed to resolve this ambiguity, culminating in a border treaty in 1984 that formally included bridges and footbridges within the shared jurisdiction.
Today, this condominium operates under a system of concurrent jurisdiction, meaning that both German and Luxembourgish laws can be applied, with bilateral agreements in place to address potential legal conflicts. This rare example of shared sovereignty allows police forces from both countries to operate within the shared territory. Officers from either nation can engage in joint patrols and intervene when offenses occur on shared rivers or bridges. The jurisdiction for subsequent legal proceedings often depends on factors such as the identities of those involved and the specifics of the incident.
The German-Luxembourgish condominium remains an exceptional case of shared sovereignty within Europe, featuring a border that functions distinctly from the conventional boundaries that typically separate nations. This arrangement highlights a collaborative approach to governance and law enforcement, emphasizing cooperation between Luxembourg and Germany in managing this jointly held region.