The battle of Kousséri originated in French plans to occupy the Chari-Baguirmi region. In 1899–1900, the French organized three armed columns, one proceeding north from Congo, one east from Niger and another south from Algeria. The objective was to link all French possessions in Western Africa, and this was achieved April 21, 1900 on the right bank of the Chari in what is now Chad opposite Kousséri, in what today is northern Cameroon.
In 1899, Sudanese warlord Rabih az-Zubayr could field some 10,000 infantry and cavalry, all provided with rifles (except for 400 rifles, these were mostly obsolete), plus a great number of auxiliary troops equipped with lances or bows. His forces held fortified garrisons at Baggara and Karnak Logone.
In 1899, Rabih received in Dikoa the French representative Ferdinand de Béhagle. The talks between them degenerated, and Béhagle was arrested. On July 17, 1899, Lieutenant Bretonnet, whose force was then sent by France against Rabih, was killed with most of his men at Togbao at the edge of the Chari River, present-day Sarh. Rabih gained three cannons from this victory (which the French later retook at Kousséri) and ordered his son Fadlallah, whom he had left in Dikoa, to hang Béhagle.
Kousséri is a city in Far North Province, Cameroon, lying on the border with Chad, across the Chari River from N'Djamena. It is the capital of the Logone-et-Chari department. It is a market town, and its population has recently been swollen by refugees from Chad. It had a population of 89,123 at the 2005 Census.
Kousséri was part of the Bornu Empire. In March 1846 Omar (son of Sheik Mohammed), nominal general of the Bornu sultan Ibrahim suffered a defeat at Kousséri.
In 1900 the village was occupied by soldiers of Rabij az-Zubayr (Rabih), a Sudanese warlord. On 3 March it was taken by the combined forces of two French expeditions, one under Major Lamy from Algeria and the other under Lt. Paul Joalland from Senegal and local forces opposed to Rabih. Rabih was not in Kousseri at the time but established himself in a fort on the right bank of the Chari. Lamy did not think he had sufficient forces to attack Rabih immediately, but waited until the beginning of April when he was joined by a third expedition that was coming up the Chari under Emile Gentil. When he arrived the combined forces crossed the Chari and attacked Rabih. The battle of Kousséri was a decisive battle which secured French rule over Chad.