At the turn of the 20th century the clash of interests of France and Britain, the two leading colonizing powers, occurred all over the world, not avoiding Southeast Asia. The article examines the history of the French explorations of highland Tonkin and Chinese Yunnan province as a means of enforcing stronger colonial hold over Vietnam. A large number of military officers, missionaries etc. have explored this highland region inhabited by multiple ethnic groups, previously almost unknown to the Europeans. In the 1860–1870s the first expeditions studied the flow of Mekong, Salween, Irrawaddy and the Red River. The results were published as books and reports by F. Garnier, E.D. de Lagrée, É. Rocher, H. d’Orléans. P. Lefèvre-Pontalis, etc. After the establishment of the French protectorate over Tonkin in the 1880s, military officers, assigned to secure stability in this tumultuous area, conducted ethnographic studies. The reports by Captain A. Bonifacy and Colonel M. Abadie were especially professional and academically valuable. The struggle for influence over Yunnan was particularly intense between the French and the British empires. The border demarcation by the Sino-French commission had been completed by 1896; the construction of Kunming–Haï Phong railroad had been completed by 1910. Diplomats and engineers participated in the project and produced books and papers. Catholic missionaries of the Société des Missions Etrangères de Paris delved into the lifestyle and language of the local ethnic groups. They penned both more or less academically sophisticated ethnographic studies and dictionaries of the local languages.
Ekaterina A. Zavidovskaya (Thu,) studied this question.