In Algeria, Equatorial Africa and Madagascar, the electorate was divided into two colleges (or rolls, as the British would've called them) - one for "citoyens du statut français" (French-born citizens and those natives who had attained citizenship through education, military service or similar, and were fully under the jurisdiction of French law) and one for "citoyens du statut personnel" (everyone else). Only the former had been allowed to vote at all under the Third Republic, and the latter were massively underrepresented even under the Fourth.
For instance, in Madagascar in 1951, there were some 30,000 voters on the French roll and 850,000 on the statut-personnel roll, but the former got two seats and the latter three. There were only about 10,000 citoyens du statut français in all of Equatorial Africa, so I honestly have no clue why they kept the separate roll there but not in West Africa.