<P> The next objective of the French was to take full control of the Tonkin . In October 1883, Courbet was placed in command of the Tonkin Expeditionary Corps . In December 1883, he led the Sơn Tây Campaign against the Black Flags . French casualties were heavy (83 dead and 320 wounded), but the Black Flags were very weakened as a result of the campaign . </P> <P> The Bắc Ninh Campaign (March 1884) was one of a series of clashes between French and Chinese forces in Tonkin (northern Vietnam) in the period . The campaign, which lasted from 6 to 24 March, resulted in the French capture of Bắc Ninh and the complete defeat of China's Guangxi Army . </P> <P> China, the traditional overlord of Vietnam, kept contesting French influence in the area and was supporting Annam as well as the Black Flags on its territory at the frontier with Tonkin . Although a treaty had been signed between France and China (11 May 1884 the Tientsin Accord) promising Chinese evacuation from Tonkin, military confrontations continued as in the Bắc Lệ ambush (June 1884). These tensions led to the Sino - French War (1884--85), which ultimately forced China to totally disengage from Vietnam and confirmed the French possessions . </P> <P> French Indochina was officially formed in October 1887 from Annam, Tonkin, Cochinchina (which together form modern Vietnam) and the Kingdom of Cambodia following the Sino - French war (1884--1885). Jean Antoine Ernest Constans became the first Governor - General of French Indochina on 16 November 1887 . Laos was added after the Franco - Siamese War of 1893 . </P>

Why were the vietnamese against the french control