I'll say it again because I grew up in Europe on various types of cinema, foreign doesn't mean good. This is no French classic; it's a minor film directed by a minor actor. The affectation in some of the camera setups is typical of actors trying to be cute instead of being good storytellers. Of course, the movie has a refreshing quality because it lacks the predictable tropes of your average American fare (happy/clear endings, theatrics/histrionics and life lessons). And watching those kids is borderline interesting. But really, the film has little ambition. Like many independent works, it just tries to tell A story with an honest eye, but the story has to be original and/or interesting if the acting and directing are going to be this flat.

I have to read subtitle but the kids are so good... plot is so real..

More a story about Yuki than Nina. If this was an American movie, it would be a story about two 9 year old best friends being torn apart. It would be written to make the kids happy, and it'd have a sappy ending,....but , it's not.
This is a French/Japanese movie and the goal here is different. In the end it's a story about change & acceptance. Adults make decisions, and children must live w/ those decisions. Real life is messy, but it's okay in the end.
The direction and writing is a little dis-jointed, the cinematography is a mix of good & bad.
The last half-hour of the movie is awkward & hard to follow,....but.....
The characters are likable, the dialog is believable. The little girls are earthy, gentle, & real in a way that American kids never are.
Worth your time if you'd like to watch a Family movie that different from the usual "fluff".