The French colonial empire comprised the overseas colonies, protectorates, and mandate territories that came under French rule from the 16th century onward. A distinction is generally made between the "First French colonial empire", that existed until 1814, by which time most of it had been lost or sold, and the "Second French colonial empire", which began with the conquest of Algiers in 1830. On the eve of World War I, France's colonial empire was the second largest in the world after the British Empire.

The French conquest of Algeria took place between 1830 and 1903. In 1827, an argument between Hussein Dey, the ruler of the Regency of Algiers, and the French consul escalated into a blockade, following which the July Monarchy of France invaded and quickly seized Algiers in 1830, and seized other coastal communities. Amid internal political strife in France, decisions were repeatedly taken to retain control of the territory, and additional military forces were brought in over the following years to quell resistance in the interior of the country.