Belgium

The Belgian flag uses black, yellow, and red derived from historic heraldic colors associated with Brabant and other provincial arms. After the 1830 Belgian Revolution, an early horizontal red-yellow-black version was quickly replaced by the vertical tricolor, inspired by the French flag. The colors were confirmed in the constitution on 23 January 1831, and the flag became the national standard on 12 October 1831. Belgium’s official flag proportion is 13:15, though it is often reproduced as 2:3.