The small French contingent, holed up in a fortification at Mazagran, near the port city of Mostaganem, withstood several days of assault by `Abd al-Qādir 's troops.

Lieutenant Colonel Dubuessil, the commander of the French garrison at Mostaganem, ordered Captain Lelièvre and 122 men from the 10th Company of the Battalion of Africa to occupy a small fort in the town of Mazagran.

According to some sources, Algerian resistance forces under the command of Ben Khami (one of Abdal-Qādir's lieutenants) began arriving and surrounding the fort as early as the evening of 1 February, with actual organized assault beginning either then or the next day.

Khami's force, initially reported by the French as numbering anywhere from ten to twenty thousand (although later analysis suggests it was considerably smaller) consisted primarily of cavalry.

[8] One correspondent to a British military journal took issue with the Morning Chronicle's reporting, describing an encounter with an unidentified French officer who claimed that something resembling the affair took place, but was significantly puffed up.