The Algerian immigration, which began before the First World War, does not seem to have posed particular problems at the outset. Only the French settlers in Algeria looked unfavourably on its growth, insofar as this threatened to reduce the pool of cheap labour they were accustomed to having at their disposal. But the war was to change things completely. Summoned en masse to serve as soldiers or civilian workers in France, the Algerians discovered an industrial society, with its wealth and the relative respect accorded to its workforce, even when this was composed of immigrants. Once the war was over, many sought to remain in France or to return there, fleeing the endemic poverty of their own country, the oppression of the settlers and the constraints of an authoritarian society. Alerted by the administrators in Algeria, who provided striking descriptions of the consequences of the war on the social, sexual and political behaviour of the native population, the French public authorities concluded that emigration constituted a threat for France's continued presence in Algeria and chose to give preference to European immigrants. The Algerians were thus officially declared undesirable in France. In spite of this strategy, the Algerian emigration, with its structural causes, continued and the Cartel government (1924-25), yielding to pressures from the colonial lobbies, introduced regulations to limit the exodus. The government did not go so far as to prohibit it, however, for as such a measure did not seem possible in the political and diplomatic context of the moment. And in spite of the ruthless arsenal of regulations deployed against it, the emigration continued.

Since this flow could not be totally curbed, efforts were directed at better controlling it, which, in all the large cities of France, gave rise to the SAINAs (Services des Affaires Indigenes Nord-Africaines, or North African native affairs departments). This confusion of police action and a very particular kind of social services was to have the effect of isolating the Algerians from the rest of the French or immigrant population and, for a long time, blocking access to all the paths by which foreigners normally blend into French society :  the immigration of women and children (who then attend public schools), living accommodations in workers' housing estates or neighbourhoods (rather than in rented rooms exclusively inhabited by fellow Algerians), which give rise to social exchanges facilitating integration, contacts with ordinary social services and so on. Systematically used as scabs during strikes or as an attack force by right-wing leagues with the complicity of the police, the Algerians were cut off from the unions and thus constituted a lumpen-proletariat detested by the rest of the working-class population. Having no national State behind them for protection, they became the pariahs of French society even as their influx was increasing and starting to take the form of what it would soon become a mass immigration destined to take root in France.