During the Sino-French War (August 1884 to April 1885) Feng was placed in command of a chiefly Zhuang armed force in South China, composed mainly of local peasantry and some of Feng's retired imperial troops. On 23 February 1885 the misdeployment of Feng's troops too far from the battlefield was a major factor in the defeat of China's Kwangsi Army in the Battle of Đồng Đăng. Feng atoned for his incompetence exactly one month later. On 23 and 24 March 1885 Feng's forces were present at the Battle of Bang Bo, in which Francois de Negrier's 2nd Brigade was defeated at Zhennanguan on the Kwangsi-Tonkin border. The Chinese had heavily fortified their position, and although the French captured a number of Chinese outworks on 23 March, their attacks on 24 March failed to make any headway. Eventually the French were counterattacked and forced to retreat, with casualties of 74 killed and 213 wounded. Chinese casualties were far higher.