In 1886, the French separated Tonkin from the Nguyễn imperial court in Huế by establishing the office of "Viceroy" (經略衙, Kinh lược nha).

In 1945, the emperor Bảo Đại rescinded the Patenôtre Treaty, ending the French protectorates over Annam and Tonkin, creating the Empire of Vietnam, a Japanese puppet state.

[5] Following the surrender of Japan, ending World War II, the Việt Minh launched the August Revolution which led to the abolition of the Nguyễn dynasty and the Proclamation of Independence of the Democratic Republic of Vietnam.

During the Sino-French War (1884–85), the northernmost part of Vietnam, Tonkin (then considered a crucial foothold in Southeast Asia and a key to the Chinese market), was invaded by the French.

These territories were fairly arbitrary in their geographic extent as the vast majority of the Vietnamese regarded their country as a single land and minor resistance to French rule continued over the next 70 years to achieve an independent state.

On June 3, 1886, the Nguyễn emperor Đồng Khánh delegated all of his powers in Tonkin to a Kinh lược sứ (經略使, equivalent of Viceroy), who acted under French supervision.

Under French economic plans, mines yielding gold, silver, and tin as well as the farming of rice, corn, and tea powered Tonkin's economy.

[10] At the end of the war, the north of Vietnam (including Tonkin) saw a sphere of influence by China while the south was briefly occupied by the British for French forces to regroup and regain control.

Harry Truman at the Potsdam Conference, stated an intention to hand the region back to French rule, a sharp contrast to Franklin D. Roosevelt's strong opposition to colonialism and commitment to support the Viet Minh.

[12][15] A conseil du protectorat composed of important officials and representatives from the chambers of agriculture and commerce, assisted the resident in performing his duties.

[17] Despite its name the House of People's Representatives was not democratically elected but was composed of appointed Vietnamese elites and it only discussed issues related to taxation rather than legislation.