Before the 2000s, most Vietnamese animators had to study in the Soviet Union and Russia in the form of aid. I heard that, when Vietnam had a civil war (as you know, in the 1960s-70s Canada sent military medical experts to South Vietnam), some East German and Soviet film experts also followed the secret route to Tây-Ninh war zone (Vietnam - Cambodge border) to help Vietcong learn filmmaking techniques, because these people are all very young and have low education. After reunification, these people combined with Southern film experts (most of whom were influenced by French animation, some even went to Hollywood to study professionally), so it's strange, in the 1980s our animation flourished. However, in the 1990s, there was a serious recession because of the "invasion" of Japanese animation. To be honest, young Vietnamese people don't know much about French, American, Russian and European-American animation in general.
So Đặng-Nhân-Lập is not a famous filmmaker ; here, I tried translating the film into English subs. So far it is still a classic one in Vietnam : https://www.youtube.com/watch?v=lTpFz8DxL30