A rain-hit third practice for the French MotoGP left world champion Joan Mir and current rider's standings leader Francesco Bagnaia outside the top 10 times and destined for a Q1 battle later on Saturday.
Six-time world champion Marc Marquez continued his road back from injury by setting the quickest time on his Honda in a session hampered by a downpour at the start.
The wet conditions made it impossible for any riders to shake up the top 10 combined times from Friday's practice, with this group heading straight to Q2.
French home favourites Johann Zarco and Fabio Quartararo top the time sheets with Marquez in eighth, Valentino Rossi ninth and Takaaki Nakagami in 10th.
Seventh quickest Australian Jack Miller suffered his second crash of the weekend on his Ducati but escaped unhurt.
With only the two quickest riders from Q1 joining this group in Q2 and the fight for pole Mir and Bagnaia, along with the likes of Alex Rins and Brad Binder, are in for a tense afternoon at Le Mans' Bugatti circuit.
Combined times after the first three practice sessions
1. Johann Zarco (FRA/Ducati-Pramac) 1min 31.747sec, 2. Fabio Quartararo (FRA/Yamaha) at 0.095s, 3. Maverick Vinales (ESP/Yamaha) 0.389, 4. Pol Espargaro (ESP/Honda) 0.390, 5. Franco Morbidelli (ITA/Yamaha-SRT) 0.532, 6. Miguel Oliveira (POR/KTM) 0.549, 7. Jack Miller (AUS/Ducati) 0.614, 8. Marc Marquez (ESP/Honda) 0.885, 9. Valentino Rossi (ITA/Yamaha-SRT) 0.922, 10. Takaaki Nakagami (JPN/Honda-LCR) 0.964