Brussels

Holy Roman Empire de facto · 1789 – October 17, 1797 (from the border data)
France de facto · October 17, 1797 – May 23, 1808 (from the border data)
France de facto · October 14, 1808 – April 12, 1814 (from the border data)
Netherlands de facto · March 16, 1815 – June 8, 1839 (from the border data)
Belgium de facto · October 4, 1830 – June 25, 1940 (from the border data)
German Empire de facto · August 20, 1914 – November 11, 1918 Military occupation (from the border data)
Germany de facto · May 16, 1940 – June 21, 1940 Military occupation (from the border data)
Germany de facto · June 26, 1940 – August 31, 1944 Military occupation (from the border data)
Belgium de facto · since 1945 (from the border data)