Bottas ended first practice at the Circuit Paul Ricard 0.3s clear of Mercedes teammate Lewis Hamilton.

Max Verstappen edged out the Finn by just 0.008s in the second session, although Bottas set his fastest time on the medium tyre having been unable to improve on the softer compound.

A key talking point for this weekend has been Mercedes’ decision to swap chassis between its drivers.

Bottas is unsure his return to form in France this weekend is due to running Hamilton’s chassis.

“It’s such a different track, but the balance is good, the tyres are working well, I’m confident with the car, I can trust the car – I think that’s the biggest difference,” Bottas said.

“It’s hard to say if it’s the chassis or the track conditions, but there’s a lot better feeling than two weeks ago [in Baku] – that’s for sure – and I felt we started the weekend on the right foot. Everything was feeling OK, being comfortable and pretty fast with the car so far.”

Track temperatures at Le Castellet were over 40 degrees, causing drivers to struggle when running on the C4 soft tyre during the qualifying simulations.

It’s likely teams will try and get through into Q3 on the C3 medium tyre, but Bottas isn’t giving anything away.

“Can’t reveal everything,” Bottas added. “Honestly my feeling was that between the medium and the soft tyre there wasn’t a big difference in terms of single lap performance, but in the long run the Medium is better, for sure.

“I would imagine that everyone would like to start with the mediums, because you can go further, but for that you need to be quick enough to get through in Q2.”

Unlike in Monaco and Azerbaijan - where Ferrari was in the mix - it looks like it will be a two-way fight again at the front between Mercedes and Red Bull.

“I think it’s fairly close,” Bottas explained. “We expected them to be strong but for now it feels like it’s between us and Red Bull, but it’s a very different track from Baku or Monaco, so we’ll see tomorrow. I’m sure they’ve got a lot more to come and so do we.”