The Treaty of Saigon was signed on June 5, 1862, between representatives of the French Empire and the last precolonial emperor of the House of Nguyen, Emperor Tự Đức. Based on the terms of the accord, Tự Đức ceded Saigon, the island of Poulo Condor and three southern provinces of what was to become known as Cochinchina (Bien Hoa, Gia Dinh, and Dinh Tuong) to the French. The treaty was confirmed by the Treaty of Hué signed on April 14, 1863.
The Second Treaty of Saigon, signed on March 15, 1874, was negotiated by Paul-Louis-Félix Philastre in 1874 and reiterated the stipulations of the previous agreement. Vietnam recognized the full sovereignty of France over the three provinces captured by admiral La Grandière in 1867. The Red River (Song Hong) was opened for trade as well as the ports of Hanoi, Haiphong and Qui Nhơn. Although France returned Hanoi, the Vietnamese emperor was anxious to get help from China. As a result, both France and China claimed sovereignty over Vietnamese territory. In March 1882, the first civilian governor of Cochin China, Le Myre de Vilers, deemed the treaty of 1874 unfulfilled. This led to the occupation of Hanoi on April 27, 1882.
The Second Treaty of Saigon