By 1884, the entire country was under French rule, with the central and northern parts of Vietnam separated into the two protectorates of Annam and Tonkin. The three entities were formally integrated into the union of French Indochina in 1887.[91][92] The French administration imposed significant political and cultural changes on Vietnamese society.[93] A Western-style system of modern education introduced new humanist values.[94] Most French settlers in Indochina were concentrated in Cochinchina, particularly in Saigon, and in Hanoi, the colony's capital.[95]

During the colonial period, guerrillas of the royalist Cần Vương movement rebelled against French rule and massacred around a third of Vietnam's Christian population.[96][97] After a decade of resistance, they were defeated in the 1890s by the Catholics in reprisal for their earlier massacres.[98][99] Another large-scale rebellion, the Thái Nguyên uprising, was also suppressed heavily.[100]