9e Regiment Infantrie Coloniale (RIC) was in Hanoi during the 1930s. They fought in Indochina against the Japanese in WW2. The French Colonial Infantry became known as the “Troupes de Marine” after 1958 due to decolonization. Despite this name and the anchor symbolism, they were officially part of the French Army (source: https://www.globalsecurity.org/military/world/europe/fr-armee-troupes-de-marine.htm ), not the Navy (The Fusiliers Marins are part of the Navy, source: https://www.globalsecurity.org/military/world/europe/fr-marine-fusiliers-marins.htm ).
This uniform set was locally tailored in Hanoi. Like many other nations at the time, and still today, officers were responsible for providing their own uniforms.
Anchor on button to represent overseas colonial service.
Extra insignia was found in the pockets:
Horseback riding breeches cut.
Mle 1931 pith helmet was also worn in same time period as the uniform above. This one was acquired separately and did not belong to same officer as uniform above. “Snake skin” headband is probably synthetic (not real snake skin).