According to Ben Kiernan, colonization and genocidal massacres proceeded in tandem. Within the first three decades (1830–1860) of French conquest, between 500,000 and 1,000,000 Algerians, out of a total of 3 million, were killed due to massacres and war.[52][53] During this period, the French destroyed mosques and other Islamic buildings and converted them into Catholic Churches.[54][55][56] Atrocities committed by the French during the Algerian War during the 1950s against Algerians include deliberate bombing and killing of unarmed civilians, the use of napalm to indiscriminately burn villages,[57][58] rape, torture, executions through “death flights” or burial alive, thefts and pillaging.[59][60][61] Up to 2 million Algerian civilians were also deported in internment camps.[62]

During the Pacification of Algeria (1835–1903) French forces engaged in a scorched earth policy against the Algerian population. Colonel Lucien de Montagnac stated that the purpose of the pacification was to “destroy everything that will not crawl beneath our feet like dogs.”[63] The scorched earth policy, decided by Governor General Thomas Robert Bugeaud, had devastating effects on the socio-economic and food balances of the country: “we fire little gunshot, we burn all douars, all villages, all huts; the enemy flees across taking his flock.”[63] According to Olivier Le Cour Grandmaison, the colonization of Algeria led to the extermination of a third of the population from multiple causes (massacres, deportations, famines or epidemics) that were all interrelated.[64] Returning from an investigation trip to Algeria, Tocqueville wrote that “we make war much more barbaric than the Arabs themselves […] it is for their part that civilization is situated.”[65]

During the Algerian War (1954–1962), the French used deliberate illegal methods against the Algerians, including (as described by Henri Alleg, who himself had been tortured, and historians such as Raphaëlle Branche) beatings, torture by electroshock, waterboarding, burns, and rape.[61][76] Prisoners were also locked up without food in small cells, buried alive, and thrown from helicopters to their death or into the sea with concrete on their feet.[61][77][78][79] Claude Bourdet had denounced these acts on 6 December 1951, in the magazine L’Observateur, rhetorically asking, “Is there a Gestapo in Algeria? .”[80][81][82] D. Huf, in his seminal work on the subject, argued that the use of torture was one of the major factors in developing French opposition to the war.[83] Huf argued, “Such tactics sat uncomfortably with France’s revolutionary history, and brought unbearable comparisons with Nazi Germany. The French national psyche would not tolerate any parallels between their experiences of occupation and their colonial mastery of Algeria.” General Paul Aussaresses admitted in 2000 that systematic torture techniques were used during the war and justified it. He also recognized the assassination of lawyer Ali Boumendjel and the head of the FLN in Algiers, Larbi Ben M’Hidi, which had been disguised as suicides.[84] Bigeard, who called FLN activists “savages ,” claimed torture was a “necessary evil .”[85][86] To the contrary, General Jacques Massu denounced it, following Aussaresses’s revelations and, before his death, pronounced himself in favor of an official condemnation of the use of torture during the war.[87] In June 2000, Bigeard declared that he was based in Sidi Ferruch, a torture center where Algerians were murdered. Bigeard qualified Louisette Ighilahriz’s revelations, published in the Le Monde newspaper on June 20, 2000, as “lies.” An ALN activist, Louisette Ighilahriz had been tortured by General Massu.[88] However, since General Massu’s revelations, Bigeard has admitted the use of torture, although he denies having personally used it, and has declared, “You are striking the heart of an 84-year-old man.” Bigeard also recognized that Larbi Ben M’Hidi was assassinated and that his death was disguised as a suicide.

In 2018 France officially admitted that torture was systematic and routine.[93][94][95]

In October 2021, the office of Algerian president Abdelmadjid Tebboune stated that 5.6 million Algerians died during French colonial rule.[96][97][98] According to The New Arab, the historian Mohammed Al-Amin estimates that the total Algerian death toll during the 132 years of French colonial occupation could be as high as 10 million.[98]