This is a good movie, imao; that is an understatement. 1973 French movie: Animation, Drama, Sci-Fi.
Found a YouTube Part 1 in English, after an interesting write-up on a feedly reader site. Yes, it's very trippy. The other three parts have English subtitles, or the entire movie can be seen in French at the link. According to IMDB: said to be based on the Soviet Occupation of the Czech Republic.
Watched the movie on Thor'sDay, Saturn's Day random art work from the movie popped up on feedly several times, like little gifts.