The Battle of Bang Bo was a major Chinese victory during the Sino-French War. The battle, fought on 23 and 24 March 1885 on the Tonkin-Guangxi border, saw the defeat of 1,500 soldiers of General François de Négrier's 2nd Brigade of the Tonkin Expeditionary Corps by a Chinese army under the command of the Guangxi military commissioner Pan Dingxin. The battle set the scene for the French retreat from Lang Son on 28 March and the conclusion of the Sino-French War in early April in circumstances of considerable embarrassment for France.