The European invasion of Central African territory began in the late 19th century during the Scramble for Africa. Europeans, primarily the French, Germans, and Belgians, arrived in the area in 1885. France seized and colonized Ubangi-Shari territory in 1894. In 1911 at the Treaty of Fez, France ceded a nearly 300,000 km2 portion of the Sangha and Lobaye basins to the German Empire which ceded a smaller area (in present-day Chad) to France. After World War I France again annexed the territory. Modeled on King Leopold's Congo Free State, concessions were doled out to private companies that endeavored to strip the region's assets as quickly and cheaply as possible before depositing a percentage of their profits into the French treasury. The concessionary companies forced local people to harvest rubber, coffee, and other commodities without pay and held their families hostage until they met their quotas. Between 1890, a year after the French first arrived, and 1940, the population declined by half due to diseases, famine and exploitation by private companies.