Yan is a successful artist. One day he is waiting for his date Florence to turn up at his apartment. As the doorbell rings, he finds another young woman in underwear on his doorstep: his neighbor Eva! She tells him she locked herself out of her apartment and insists that he helps her. Whilst Yan is trying to enter Eva's apartment via their adjoining balcony, his phone rings. It is Florence, and she is not impressed when a female voice answers the phone. At this point, Eva's rabidly jealous boyfriend Boris returns home. Seeing Yan in his apartment, he deduces that Eva has been having an affair behind his back. Florence then turns up and Yan tries in vain to explain the situation. By chance, Florence's husband suddenly puts in an appearance. After that, it all starts to get a bit complicated.

The series follows the adventures of lighthearted Jean-Paul Moulin, a police Commissaire, and his team as they solve crimes.