In 1863, King Norodom consented to an arrangement with the French to make a protectorate over his kingdom. The state continuously went under French pilgrim standard.
Amid World War II, the 1940–41 Franco-Thai War left the French Indochinese pioneer dominant presences in a position of shortcoming. The Vichy government consented to an arrangement with Japan to permit the Japanese military travel through French Indochina.
Then the Thai government, under the expert Japanese administration of Field Marshal Plaek Phibunsongkhram, exploited its position and attacked Cambodia's western areas.
Cambodia's circumstance toward the end of the war was disordered. The Free French, under General Charles de Gaulle, were resolved to recoup Indochina, however they offered Cambodia and the other Indochinese protectorates a deliberately surrounded measure of self-government. Persuaded that they had a "cultivating mission", they imagined Indochina's interest in a French Union of previous settlements that mutual the normal experience of French society.