Using Napoleon's 1808 contingency plan for the invasion of Algeria, 34,000 French soldiers landed twenty-seven kilometers west of Algiers, at Sidi Ferruch, on June 12, 1830. To face the French, the Dey of Algiers assembled 7,000 janissaries, 19,000 troops from the Beys of Constantine and Oran, and about 17,000 Kabyles. The French established a strong beachhead and pushed toward Algiers, thanks in part to superior artillery and better organization. Algiers was captured after a three-week campaign, and Hussein Dey fled into exile. French troops raped, looted (taking 50 million francs from the treasury in the Casbah), desecrated mosques, and destroyed cemeteries. It was an inauspicious beginning to France's self-described "civilizing mission," whose character on the whole was cynical, arrogant, and cruel.
Hardly had the news of the capture of Algiers reached Paris than Charles X was deposed, and his cousin Louis Philippe, the "citizen king," was named to preside over a constitutional monarchy. The new French government, composed of liberal opponents of the Algiers expedition, was reluctant to pursue the conquest ordered by the old regime, but withdrawing from Algeria proved more difficult than conquering it. A parliamentary commission that examined the Algerian situation concluded that although French policy, behavior, and organization were failures, the occupation should continue for the sake of national prestige. In 1834 France annexed the occupied areas, which had an estimated Muslim population of about 3 million, as a colony. Colonial administration in the occupied areas -- the so-called régime du sabre (government of the sword) -- was placed under a governor general, a high-ranking army officer invested with civil and military jurisdiction, who was responsible to the minister of war.
Whatever initial misgivings Louis Philippe's government may have had about occupying Algeria, the geopolitical realities of the situation created by the 1830 intervention argued strongly for reinforcing the French presence there. France had reason for concern that Britain, which was pledged to maintain the territorial integrity of the Ottoman Empire, would move to fill the vacuum left by a French pullout. The French devised elaborate plans for settling the hinterland left by Ottoman provincial authorities in 1830, but their efforts at state building were unsuccessful on account of lengthy armed resistance.