The movie follows 20 year old Amélie (Pauline Étienne) through her time in Tokyo. She's Belgian, but spent the first five years of her life in Japan and has now returned to what she considers her true home. She initially attempts to support herself by tutoring French while hoping to become a writer.
The movie is based on a novel of the same name by Belgian writer Amélie Nothomb. The degree to which it's fictionalized is unclear - Wikipedia's entry on the book only mentions that it's a "autobiographical novel." Some changes (and similarities) are obvious from a quick glance at the Wikipedia page about Nothomb: she lived in Japan from the age of 2-5, while her book character was born there. The book was published in 2007, but the events of the movie end because of the Fukushima disaster (2011).
Amélie (the movie character) is determined that Japan is her true home - but her experiences with her one and only student (Rinri, played by Taichi Inoue) who also becomes her lover, make it clear that many things about Japanese culture are entirely opaque to her and likely to remain that way. They were certainly opaque to me. Rinri's character also throws in the strange contrast between the French-speaking Belgian woman who desperately wants to be Japanese, and the Japanese man who desperately wants to be French. The first two thirds of of the movie consists of a lot of goofiness and discomfort: she's a bit of a goof, it's played up, and the movie concentrates on her fish-out-of-water status with the Japanese people she interacts with - not really for humour, but there's a huge dose of awkwardness. The last third is very melancholy as she tries to figure out what the hell she's doing with herself, her life, and her Japanese boyfriend. The end is forced on her and us and isn't very satisfactory or conclusive. While Étienne is a fairly good and quite charming actress and the lessons in Japanese culture were interesting, I'm not big on goofy-awkward and overall found the whole thing kind of so-so.