Random art movie😅🫡

Hello! I’m looking for an art film, where the characters are a younger boy and his sister, as well as an older man. The entire film takes place in a flat, which the siblings break into at the beginning of the movie, and the closing scene shows them leaving the street.

What I still remember from the film is that they decorate the apartment as if they were in a cave, and somehow, with the scenes, they wanted to convey the concept of birth. The film is dominated by red colors, and that’s about all I remember from it.

If I remember correctly, the language was French/Spanish/Portuguese