World championship leader Max Verstappen set the quickest time in practice for the French Grand Prix at Circuit Paul Ricard on Friday but the Red Bull driver was only marginally faster than the two Mercedes cars. 

The Dutchman was just 0.008 seconds ahead of Valtteri Bottas, who had topped the first session, with Lewis Hamilton only 0.253secs off the pace. 

Verstappen improved his time in the second session with a switch to soft tyres while Bottas set his best time on the mediums. 

"It's been a good end to the day and we improved quite well," said Verstappen.

"It's still really difficult around here as the track is so open and it's quite windy which means it isn't always easy to nail the lap. 

"It's hard to say where we will be tomorrow (Saturday) and you never know what people will find overnight.

"For sure I expect it to be very tight and it definitely won't be easy."

Hamilton, who is four points behind Verstappen after six rounds of the championship, complained of car balance issues during his race simulations

"Quite a struggle this weekend. Probably for everyone," said Hamilton after the session.

"I don't know if it's the track surface or the track temperature, or these inflated tyres. They have put the pressures up higher than ever before, one of the highest, but we are all sliding around and it's a struggle out there for everyone.

"That said, our times are not that bad. We are close to the front, in the fight at least."

It marked a significant improvement for Bottas who is sixth in the title race and facing regular rumours that he is to be replaced by George Russell. 

"The sensations are much better than two weeks ago (in Baku)," said the Finn. 

"We started off on the right foot. I'm comfortable and pretty fast. The car is balanced, the tyres are behaving well. I can be confident behind the wheel, that's the main difference."

The two Aston Martins also ran on mediums with Sebastian Vettel crashing during the first session. 

Mick Schumacher was another to hit the barriers in his Haas. 

Fernando Alonso was fourth fastest in his Alpine with Charles Leclerc fifth in the Ferrari. 

The third practice session takes place at 1000GMT Saturday and is followed by qualifying at 1300GMT.