Yep, this one is quite good:
http://www.radarsfixes.com/The only fixed site on the Le Mans route is the one on the Paris peripherique. But on the way to the race you're better off watching out for the ad hoc speedtraps. If last year's form is anything to go by, they'll choose a spot about 2 hours/ 200km from the track, on a stretch of road between two roundabouts. They set up roadblocks at each roundabout and mount a camera in a van on the central reservation. The cars being booked are hidden in a layby out of sight of oncoming traffic. If you drive past the trap, they catch you at the next roundabout.