Paul is the narrator, and a writer who has a block, so for financial reasons he's also working with his brother in Saint-Malo, who is carrying on the family driving school business. This gives Adam a great opportunity to pad the book out and introduce the reader to several more characters who are scarcely believable not so much in themselves but as a general group of students Paul happens to get – although they're none the less interesting for that.
There's the troubled young Justine who likes to take a break in the lesson in a café and on one occasion throws a funny spell, leading to Paul picking up the tab from the hotel he leaves her to sleep her troubles off in; then there's Élise, the seventysomething widow who invites Paul in for several drinks – there's a disturbing amount of drinking and driving in the novel – and asks him to dance with her; and we mustn't forget Brehel, who (not altogether legally: this is France) is permanently living on a trailer park after losing his job after knocking over a cyclist when he was drunk and has to re-take his test. The main trouble with all these separate stories is that they detract from the main story, making the novel in general too bitty.
In spite of Paul's faults – he and his wife (the latter in her diary) describe him as an egoist, and he tends to cope with situations he doesn't like by resorting to violence and/or heavy drinking – he's obviously a loving father, he readily helps out Justine and Élise (who unfortunately dies), and he goes out of his way to aid 'le grand' (probably too much but in any case in the end he, er, goes out the window). Even the cop Combe likes him, although he's just as much of a mess anyway, and is just as guilty of excessive drinking and driving.
This is very readable and very Olivier Adam, but there are too many parts here struggling to find a whole.
My other posts on Olivier Adam:
Olivier Adam: Je vais bien, ne t'en fais pas
Olivier Adam: Les Lisières
Olivier Adam: Le Cœur régulier
Olivier Adam: Falaises