Mauvais sang (1986)

In Paris in the near future. Aging thieves Marc and Hans owe money to a tough American woman who gives them two weeks to pay. They scheme to steal and sell a new serum for a disease that's killing lovers, but they need someone with quick steady hands. They recruit Alex, a disaffected youth who's breaking up with Lise, his 16-year-old girlfriend. In the few days before the theft, Alex becomes enchanted with Anna, Marc's young mistress. They talk, they play, they sing, but she's in love with Marc. Lise hasn't given up on Alex either, and she comes to Paris on the day of the theft. There are double crosses, a daring rescue, and, for Alex, a waiting plane. Will he make it?