Unlike the protectorates of Annam (central Vietnam) and Tonkin (northern Vietnam), Cochinchina was ruled directly by the French, both de jure and de facto, and was represented by a deputy in the National Assembly in Paris. Within Indochina, Cochinchina was the territory with the greatest European presence. At its height, in 1940, it was estimated at 16,550 people, the vast majority living in Saigon. Plantation economy The French authorities dispossessed Vietnamese landowners and peasants to ensure European control of the expansion of rice and rubber production. The French began rubber production in Cochinchina in 1907 seeking a share of the monopoly profits that the British were earning from their plantations in Malaya. Investment from metropolitan France was encouraged by large land grants allowing for rubber cultivation on an industrial scale. Virgin rainforests in eastern Cochinchina, the highly fertile 'red lands', were cleared for the new export crop. These developments contributed to the 1916 Cochinchina uprising. Insurgents attempted to storm Saigon central prison, and maintained a prolonged resistance in the Mekong Delta. 51 were hanged. As they expanded in response to the increased rubber demand after the First World War, the European plantations recruited, as indentured labour, workers from "the overcrowded villages of the Red River Delta in Tonkin and the coastal lowlands of Annam". These migrants, despite Sûreté efforts at political screening, brought south the influence of the Communist Party of Nguyen Ai Quoc (Ho Chi Minh), and of other underground nationalist parties (the Tan Viet and Việt Nam Quốc Dân Đảng—VNQDD). At the same time, the local peasantry were driven into debt servitude, and into plantation labour, by land and poll taxes. By 1930, 80% of riceland was owned by 25% of landowners, and 57% of the rural population were landless peasants working on large estates. This combination led to widespread and recurring unrest and to strikes. Of these the most significant, leading to armed confrontations, was the refusal of work by labourers Phu Rieng Do, a sprawling 5,500 hectares Michelin rubber plantation in 1930. In response to rural unrest and to growing labour militancy in Saigon, between 1930 and 1932 the French authorities detained more than 12,000 political prisoners, of whom 88 were guillotined, and almost 7000 sentenced to prison or to hard labour in penal colonies. Popular Front promise of reform In 1936 the formation in France of the Popular Front government led by Leon Blum was