eric92;
Bienvenue et comment ca va?
That appears to be a leak from the head gasket. You should wipe all the leaked oil off first. You can try re-torque of the large head studs (remove the top engine mount bracket) to 30 ft-lbs. This may help if the stud acorn nuts have backed off.
To cure the problem, you will likely have to replace the head gasket (means engine removal). How many kms on the engine? Do you get puffs of black smoke out the exhaust? Are you using a lot of oil................dipstick level drops quickly? If the head gasket is gone, you may be sucking oil from the camchain tunnel into the cylinders, and blackening the plugs.
France is very beautiful. I was over there last year for a short trip to Provence and to Normandy................enjoyed it very much.