Duval, driving the No.1 Audi R18 e-tron quarto was on a fast lap when he crashed at the Porsche Curves having just risen to second on the timesheets after 90 minutes.
Damage to the car was extensive with much of the rear end, side and roof of the car removed in the evidently high-speed impact, which also brought down the outer catch fencing.
"At 17h05 today Wednesday 11 June, the No.1 Audi left the track at very high speed at the Porsche Curves, at Marshal Post No.131. The incident occurred during the free practice session for the 82nd edition of the 24 Hours of Le Mans," says the official ACO press release.
"Conscious, the driver was taken into the care of the ACO's Medical Services, extracted from the car to an ambulance and then immediately transported to the Le Mans' Centre Hospitalier where he will undergo further examination.
"His condition is encouraging."