Answer:
To teach young generations of colonized land, that France is their ruler (Probably had propaganda education supporting the French presence in Southeast Asia.)
Step-by-step explanation:
The French had colonized parts of Southeast Asia known as French Indochina or just Indochina. This consisted of countries; Vietnam, Cambodia, and Laos. With them ruling over a territory far from its mainland, establishing schools allowed friendly relations with the locals in the colonies. This would allow to implement younger generations to look at France as a friend and true ruler of their land. Obviously this didnt work in the long run, but it was to establish a "Friendly" French presence in Indochina.