Home hero Fabio Quartararo led Andrea Dovizioso in the the opening practice session ahead of the MotoGP French Grand Prix by 0.127s, while Jorge Lorenzo was an early crasher.
Many riders opted for fresh rubber at the end of the 45-minute session for a time attack run, with MotoGP's youngest polesitter guiding his Petronas SRT Yamaha to a 1:31.986s right at the death.
Pramac's Jack Miller led the session in the early stages, the Australian guiding his GP19 Ducati to a 1:34.156s, which he soon improved to a 1:33.040s.
Championship leader Marc Marquez usurped Miller a moment later with a 1:32.915s, while Honda team-mate Lorenzo crashed at Garage Vert at the same time after running wide onto the kerb.
Miller and Marquez traded top spot again, though it was the Honda man who held the advantage with a 1:32.540s. He went just under a tenth quicker with 18 minutes left on the clock.
KTM tested at Le Mans prior to the Spanish Grand Prix, and Pol Espargaro used this recent track experience to put his RC16 top of the pile with a 1:32.341s as the session entered its final 15 minutes.
His stint at the top was short-lived, though, as Miller returned to first with a 1:32.238s, before Yamaha's Maverick Vinales – who did not fit a new tyre in the closing stages – went 0.035s faster.
Vinales' time remained in tact despite a series of improvements by those behind him, though Yamaha stablemate Quartararo would depose him as the chequered flag fell by 0.127s.
The works Ducati duo of Andrea Dovizioso and Danilo Petrucci shoved Vinales further back to fourth, with Marquez – who joined Vinales in sticking with the tyre he started the session on – completing the top five.
Espargaro's positive morning concluded with him just three tenths off the pace in sixth ahead of Miller, Suzuki's Joan Mir, Zarco and the second works Yamaha of Valentino Rossi, whose session was interrupted in the early stages by a broken chain.
Lorenzo returned to the session on his second bike after his early tumble, and was 14th at the flag with a 1:33.091s, while Jerez podium finisher Alex Rins was a low-key 17th on his Suzuki.
