Charles Leclerc and Max Verstappen ended Free Practice 1 for the French Grand Prix at almost level pegging.

The Ferrari driver proved the faster of the two on the timesheets, though a mistake from his Red Bull rival on his fastest lap cost him time.

There were no such errors for Leclerc, suggesting on raw pace it is Verstappen who holds the single lap advantage thus far.

Temperatures had soared to almost 30 degrees Celsius as the session began, with the track in the mid-50s.

Mercedes sent out reserve driver Nyck de Vries early, the Dutchman filling in for Lewis Hamilton for the session, while at Alfa Romeo Sauber it was Robert Kubica in for Valtteri Bottas.

A mixture of tyre compounds where in use, the bulk opting for soft or mediums, with Sebastian Vettel the sole runner on the hard tyres.

Inside the opening five minutes, all 20 drivers had headed out, Sergio Perez the last man out of the garage.

The initial pace was set by the usual suspects, Verstappen on a 1:35.727s setting the early pace on a set of soft tyres.

Pierre Gasly’s running was temporarily hindered by an engine problem, the Frenchman called back into the pits inside the opening 10 minutes to have his Scuderia AlphaTauri looked over before quickly rejoining proceedings.

A quarter of the way through the session, Verstappen remained fastest, his best having fallen to a 1:34.991s.

Perez had a moment at Turn 3, spinning over the Turn 4 kerbing though keeping the Red Bull out of the barrier before limping back to the pits with a set of heavily flat-spotted tyres.

The circuit proved slippery in the hot conditions, Daniel Ricciardo having a moment at Turn 12 in the upgraded McLaren.

He ran inside the top 10 at the time, though his best was more than two seconds away from the outright pace on a set of medium tyres.

The leading six runners were all on the soft tyres, including Carlos Sainz who went fastest shortly after the halfway point.

His 1:34.268s was less than a tenth quicker than Verstappen, though was somewhat misrepresentative as the Spaniard faces a 10-place penalty for taking a new Control Electronics Unit this weekend.

In reality, that’s likely to translate to a rear of grid start with Ferrari tipped to take additional power unit components before Sunday’s race.

Soon after, Verstappen improved to a 1:34.021s despite running wide as he exited De Beausset, understeering onto the kerb which upset the car on power.

Inside the final 20 minutes, the bulk of the field moved on to the soft compound tyres, Nicholas Latifi the only driver to remain on the mediums.

Leclerc went fastest with 11 minutes to run, the Ferrari driver logging a 1:33.930s, a 0.091s improvement over Verstappen’s previous effort.

The Hollywood times ended thereafter, with focus switching to race pace; high fuel and used tyres.

And so the opening hour ended with Leclerc fastest from Verstappen, with Sainz third best and George Russell fourth.

The top 10 was completed by Gasly, Perez, Lando Norris, Alex Albon, de Vries, and Daniel Ricciardo.

Free Practice 2 follows, cars set to hit track at 01:00 AEST.

Results: Formula 1 French Grand Prix, Free Practice 1