Tänak, which is making its first race in Hyundai, was in fourth place ahead of the fourth special section, Saint-Clement-sur-Durance - Freissinieres, where the accident occurred after just over nine kilometers.
Tänak drove off at high speed into a ditch and the car then continued to roll for several turns. Both Ott Tänak and his map reader Martin Järevoja are reported to be OK and left the car on their own.
However, both have been taken to hospitals for a routine check.