Michel Martenot (Louis Velle) lives somewhere in L'Île-de-France with his wife Geneviève (Pascale Roberts) and two children, and is a banker. His brother-in-law Bastien (Jacques Jouanneau) has a garage nearby. But problems start when Michel is promoted to assistant director of a branch in Paris: he's never learned to drive, and must use public transport. But transilien transport being what it (still) is, it means he will have to change four times, which means that he will have to leave early and arrive home late. He's exhausted at both ends, and using a bicycle to commute some of the way proves even worse: chains break, if you try to mend them people might think (in all your dirt), that you're a ne'er-do-well, etc.
So the only thing for Michel is learn to drive, which means renting a hotel room in Paris on weekdays until he can pass his test. And hey! He passes his theory, it's only a step away before he gets a full licence, so the family prepare for the celebration with bottles of champagne, and he hasn't the spunk to confess that he's failed miserably at the practical. Which is why he's (inexplicably to Bastien, Geneviève and kids), unable to decide on the car he wants, so he just has to stay at the hotel a little longer.
I forgot: Michel's quite a magnet to women, and when he literally bumps into Nathalie (Sandra Julien), who's also taking a driving lesson, well, they take a quick cognac in a café, she lives nearby, and what's the point of Michel returning to the hotel? But Nathalie is smitten and Michel's life is from now on more of a prison: a beautiful one, but all the same...
All the same, Nathalie gets Michel a false driving license for free, although he drives into a one-way street, a cop stops him, but hey there's a heavily pregnant woman and Michel drives her to hospital under police escort, he's a hero, and his bank thinks that too. There are many complications and misunderstandings (some of which are indirectly true, but that's another story), but as a result of his heroism Michel's promoted again – but what does that matter now that he's in an apartment in Paris with his family? Ask the cops.