 By the 1860s, there were around 4,000 residents, and the population grew to around 9,000 by the late 1880s .Casablanca remained a modestly sized port, with a population reaching around 12,000 within a few years of the French conquest and arrival of French colonialists in the town—at first as administrators within a sovereign sultanate, in 1912.The Moroccan administration of the time entrusted to the "Compagnie Marocaine" the construction of a small port whose water surface to be sheltered does not exceed 10 hectares.