In reply to StuartCJones:
It's been a problem for years and seems to go in waves. I suspect the culprits get caught, do time then, on release go back to thieving. About 10 years ago there was a gang operating out of Paris from a big white van. They could "clean out" out a car park in 2 mins flat, by smashing the windscreen or side/rear window, sweep all the contents into a dustbin bag and be gone before you could react, even if you were bouldering just a few hundred yards or so away. They acted so swiftly that even car alarms didn't deter them.
They also target Commonwealth War Graves Commission cemetery car parks on the Somme, and go particularly for GB plated cars.
A mate of mine had his car cleaned out at the Grez Sur Loing Campsite having left the car just outside outside overnight when they got back from a meal out. The campsite gates are locked at 10 pm.
No car park is safe and as others have said leave your car completely empty, the parcel shelf off, and the glove box open so that thieves can see there is nothing in the car. Even then if you are unlucky you may still get the windscreen/side/rear windows smashed.
The best thing is to leave your car at the campsite and walk to the rocks if that's possible, or leave the car in a well frequented place like outside one of the forest cafes. If you have any non climbers in the party persuade them to sit and sunbathe/read a book within sight of the car.
It's not unique to France though. I returned from climbing Puig Campana in Spain to find that the door lock on the hire car had been cut out and the door forced open. We had left nothing in the car, but had to pay the excess for the damage to the car hire company. In Spain thieves target hire cars, and I now always peel off their adverising sticker when I hire the car.
