The Treaty of Saigon, 1862

French rule in Vietnam was established over a period of fifty years through a process that had several phases. Between 1857 and 1862, the French decision to launch an expedition against Vietnam was made and implemented, resulting in the Treaty of Saigon, which granted France possession of the region surrounding Saigon. Between 1862 and 1874, Vietnamese efforts to negotiate a French departure failed as the naval officers who governed at Saigon annexed the rest of the Mekong plain to create the colony of Cochinchina. They also established a protectorate over Cambodia and sent an expedition up the Mekong, which determined that this was not a feasible route to China.

Consequently, French interest shifted to northern Vietnam and the Red River route to Yunnan, leading to a rapid conquest of the Red River plain in 1873. This, however, was quickly disavowed by the new Third Republic government of France, still reeling over the disaster of the Franco-Prussian War and the civil war between the Paris Communards and the National Guard. With the Treaty of 1874, France evacuated the Red River plain but established a loose “protectorate” over the Hue monarchy with joint Franco-Vietnamese customs stations at Hanoi, Hai Phong, and Qui Nhon.