One of the most influential behind-the-scenes French colonial officials to have ever served in Indochina. Born and raised in northern Vietnam, Cousseau learned to love the country, its culture, and above all its language. Though he held a diploma in Vietnamese from the École nationale des langues orientales vivantes in Paris, he learned the intricacies of the language on the ground in Vietnam. If there is one thing upon which Cousseau’s colonial superiors and communist opponents agreed entirely, it was the fact that he spoke flawless Vietnamese. Cousseau also studied Chinese and apparently expressed himself well in English.
Between 1927 and 1940, he worked in a variety colonial administrative positions in northern Vietnam (Moncay, Tuyen Quang, Quang Yen, and Hon Cay) before becoming the interim résident of Son La province between February 1940 and April 1943. He had also been initiated into the world of colonial intelligence during the interwar period. In 1932, the director of Political Affairs and Security for Indochina, Louis Marty, had dispatched him secretly to Yunnan to set up a “special intelligence service”, a mission which, Marty wrote, he executed perfectly. In Son La, Cousseau closely monitored the activities of Vietnamese communist prisoners held in the famous colonial prison located there. He apparently engaged them in debates over a wide range of cultural, literary, and political issues. Ranking Vietnamese communists incarcerated there who came to know Cousseau in one way or another included Le Gian, Tran Dang Ninh and Le Duc Tho. Vietnamese sources mention Cousseau’s Vietnamese wife at this time; French sources do not.
Between April 1943 and the Japanese coup de force of 9 March 1945, Cousseau headed the Local Information Office for Propaganda and the Press in Tonkin (Service local de l’information de la propagande et de la presse du Tonkin). Between December 1944 and March 1945, he also headed the Bureau of Annamese Affairs (Service des affaires annamites) in the Résidence supérieure for Tonkin. (The famous Vietnamese novelist of the 1930s, Nguyen Cong Hoan, occupied Cousseau’s position as official censor during the Democratic Republic of Vietnam’s administration of Hanoi until 19 December 1946.) Upon his release from Japanese internment, Cousseau remained in Indochina and put his knowledge of Vietnamese and Vietnamese politics in the service of 4th Republic’s colonial return to Indochina. In October 1945, he was working as the chief of the Office of Political Affairs for the commissioner for the Republic to Northern Indochina and became a close, behind-the-scenes collaborator with the French high commissioner for Indochina Georges Thierry d’Argenlieu, in 1946. He also advised Léon Pignon, political advisor in northern Indochina. The two men had known each other in the 1930s.
Following the outbreak of war in 1946, the new High Commissioner Émile Bollaert sent Cousseau to Hong Kong to open secret contacts with Bao Dai. Cousseau conducted three behind-the-scenes missions to persuade the former Emperor to join forces with the French (missions of February 1947, September 1947, and June–September 1948). Cousseau personally escorted Bao Dai to Ha Long Bay to conduct talks with Émile Bollaert in December 1947. Together with Léon Pignon, Cousseau was one of the masterminds of the Bao Dai Solution. However, Cousseau also conceded privately to the French journalist Jean Clémentin that all the “good” Vietnamese “elements” were supporting Ho Chi Minh.
In October 1948, Cousseau transferred to the Paris office of the high commissioner for France in Indochina. In March 1949, back in Vietnam, he ran the high commissioner’s service in charge of the Population montagnardes du Sud indochinois. Following his trip to France with Bao Dai in late 1950, Cousseau faded from the political scene with the creation of the Associated State of Vietnam. However, “France’s mystery man”, as American Ambassador Donald Heath put it privately in July 1954, continued to operate discreetly until Ngo Dinh Diem assumed the leadership of the State of Vietnam in 1954, and turned it into the Republic of Vietnam in 1955. The French decided it best not to allow Cousseau to return to Vietnam under Republican rule, precisely because of Cousseau’s close association with Bao Dai, who had been deposed by Ngo Dinh Diem. It is not certain whether Cousseau ever returned to his native Vietnam. His former communist competitors now established in Hanoi by 1955 knew him only too well, as did Ngo Dinh Diem. As one high commissioner privately wrote of Cousseau, il n’est pas l’homme du « service courant »; mais bien utilisé, il peut rendre les plus précieux services ». To this day, historians still know few of the actual details of those “precious services”.