In the late 19th century, Luang Prabang was ransacked by the Chinese Black Flag Army.[22] France rescued King Oun Kham and added Luang Phrabang to the 'Protectorate' of French Indochina. Shortly after, the Kingdom of Champasak and the territory of Vientiane were also added to the protectorate. King Sisavang Vong of Luang Phrabang became ruler of a unified Laos and Vientiane once again became the capital. Laos never had any importance for France[23] other than as a buffer state between British-influenced Thailand and the more economically important Annam and Tonkin. During their rule, the French introduced the corvee, a system that forced every male Lao to contribute 10 days of manual labour per year to the colonial government. Laos produced tin, rubber, and coffee, but never accounted for more than 1% of French Indochina's exports. By 1940, around 600 French citizens lived in Laos.[24] Most of the French who came to Laos as officials, settlers or missionaries developed a strong affection for the country and its people, and many devoted decades to what they saw as bettering the lives of the Lao. Some took Lao wives, learned the language, became Buddhists and "went native" - something more acceptable in the French Empire than in the British. With the racial attitudes typical of Europeans at this time, however, they tended to classify the Lao as gentle, amiable, childlike, naive and lazy, regarding them with what one writer called "a mixture of affection and exasperation."
Prince Phetsarath declared declared Laos' independence on 12 October 1945, but the French under Charles de Gaulle re-asserted control. In 1950 Laos was granted semi-autonomy as an "associated state" within the French Union. France remained in de facto control until 22 October 1953, when Laos gained full independence as a constitutional monarchy.