During this time, the First German Embassy in Luxembourg was used as the Grand Headquarters, which led to disgruntlement.

The 1914 Septemberprogramm authorized by German Chancellor Theobald von Bethmann Hollweg planned an annexation of Luxembourg into Germany as one of its federal states.

[3] During World War II, the Wehrmacht invaded Luxembourg on the night of May 9–10, 1940, to attack France and held the country until 1944.

The French Lorraine, the German Saarland and the Grand Duchy of Luxembourg today cooperate closely across borders in various areas within the framework of the Saar-Lor-Lux European Region.

Germany is Luxembourg's most important economic partner, accounting for 27% of its foreign trade volume.