For the defenders, serious estimates converge on about a thousand fighters: “a thousand warriors” (Gérardin), “nearly a thousand” according to a French estimate quoted by Hart, nearly 1,000 fighters among 7,000 refugees according to General Huré (translated by Hart), 1,200 according to Qaid ʿAli, Assou's son. The besieged population was much larger: 490 families, 2,900 people, among the last defenders of 25 March alone.
The 12,000 “men and women” and the “80,000” attackers put forward by Wikipedia rest on no consulted source; the article itself flags them as doubtful. On the French side, the sources describe two groups (Catroux west, Giraud east) made up mostly of Moroccan auxiliaries (partisan harkas and goums), backed by the Legion, spahis, artillery and aircraft.
Two distinctions remain essential: armed fighters versus the besieged population (families were present), French regulars versus Moroccan auxiliaries, the latter forming most of the assault troops. Hart notes that Aït Atta partisans sometimes replaced the bullets in their cartridges with paper on recognising kinsmen on the other side.