On March 20, 1922, Jean Desbois started his first job in French Indochina with the Public Works department in Saigon before moving to Phnom Penh in Cambodia where he worked between 1931 and 1937. During his time there, he designed the new Phsar Thmey Central Market in Phnom Penh between 1934 and 1937. Jean Desbois worked with his Excellency King Sisowath Monivong in the 1930s, and notably contributed to the design of the Le Royal Hotel in collaboration with Ernest Hébrard in 1938. He received the honorary title of Knight of the Royal Order of Cambodia in 1924.
