Marcel and Zero are respectively played by Johnny Hallyday and Renaud, two of the most famous French rock singers. In the scene where the two are fighting to decide which radio station they'll listen to, they each want to listen to their own song, Marcel wants to listen to some Johnny Hallyday, and Zero wants to listen to some Renaud.
Another in-joke: When the thieves want to take aliases to protect their identities, Marcel insists on being called "Elvis". That's because Johnny Hallyday, who plays Marcel, is known as the "Elvis of France".
When it's announced on TV news that Sami is being sought for murder, the victim is named as 'Sophie Greer'.