So ... (spoilers)
There is a retrovirus that affects the blood of those who have unprotected sex with an infected person. Alex is the son of career criminal Jean. Try as he might Alex cannot resist being drawn into his late father's world and ends up dead as a consequence. It was in his blood, so-to-speak. Alex enjoys a passing fancy with Lise, who, because she is younger, believes it is a deep love. He leaves her a paternal letter in which he counsels her on future sex to protect her from the retrovirus presumably. Alex falls in love with Anna who is unattainable and dresses in the red of blood. She is the only one who gets to wear red. She loves Marc and, thanks to Alex's poisonous words, doubts he loves her.
Not really sure what the film wanted to say about love or how to live one's life, which it seemed to be aiming at. Loved the colours and Mondrianesque graffiti adjacent to the industrial/burned out shop that is home to Marc and Anna.
A bird sings and the mountain's silence deepens.share