 In 1870, during the Franco-German War, the Empire fell, and the Château was closed.During the Franco-Prussian War, the palace was occupied by the Prussians on 17 September 1870, and briefly used as an army headquarters by Frederic Charles of Prussia from March 1871.Following the war, two of the buildings became the home of the advanced school of artillery and engineering of the French Army, which had been forced to leave Alsace when the province was annexed by Germany.