Actually, that's 1% profit. Still sucktastic.
You're in France, where the labor situation is - er - different than it is in the US, so a lot of advice you'll get here may need to be viewed from that perspective.
If you know how he runs his ship, and you can see how you can increase profitability to something decent, perhaps you can offer to run some of his other enterprises for him in exchange for a cut of any increased profit. Sounds like he's got a lot of irons in the fire, but isn't particularly good at efficiency. Bring that efficiency to him and you'll be worth a lot more than the guy running yet another of his outlets.