In reply to Somerset swede basher:
If you are worried about your car then I think you will need to leave it somewhere very visible and public, which means:
1. Leave the car in sight of the restaurant in the woods at barbizon (or if it is busy there or not open, in Barbizon itself), and then walk to Gorge d'apremont, maybe apremont bizons and do the orange and red ciruits.
2. Leave the car in Vadoue and walk to Rocher Guichot, which has orange, blue and red.
Someone else may be able to think of others, but most climbing is set a bit away from the parking, and the parking is very secluded. I think you would be safer midweek, but it is hard to know. If you check there are plenty of threads about people having their cars broken in to in Font, unfortunately.
Have a great trip.