Between 1,000 to 1,200 Algerian irregulars under Emir Abdelkader ambushed a French detachment of around 500 led by Lieutenant-Colonel Lucien de Montagnac.

[8] Although isolated French detachments were still vulnerable to surprise attacks, by 1845 a ruthless scorched earth policy employing small numbers of fast moving troops had eliminated most remaining resistance.

[10] In response, Louis-Eugène Cavaignac, governor of Oran province, despatched three separate columns to intercept him, one led by Lieutenant-Colonel Lucien de Montagnac, commander of the Ghazaouet garrison.

[11] Informed by local sources that the latter was near Souahlia, twenty kilometres to the south, the French commander left Ghazaouet at 10:00 pm on 21 September, with six companies of light infantry, and two sections of hussars, around 420 men in total.

These men withdrew into a nearby building, a monument to a local Marabout known as the saint of Sidi Brahim, and after whom the battle is named.

[19] They were surrounded, and one of the French prisoners, adjutant Captain Dutertre, was ordered to demand their surrender, but instead urged them to fight to the death, and was promptly executed.

In 1898, a monument to the "martyrs of Sidi-Brahim" was erected in Oran, but after Algerian independence in 1962, it was transformed into one of anti-colonial resistance, and the nationalist hero, Emir Abdelkader.

[23] The remains of the French soldiers killed at Sidi Brahim were initially buried at Djemmaa Ghazaouet in the Tombeau des Braves.