Lewis Hamilton has topped the first practice session of the weekend, as he put down a lap time of 1:04.838.
However, Ferrari was narrowly behind the Silver Arrows, as Sebastian Vettel split the Mercedes team, posting a time that was a tenth and a half down on Hamilton's time.
Hamilton's fastest lap was set on the soft compound, whereas Vettel placed his car into second place using the medium compound.
Bottas was third, but was delayed in getting out as the team discovered an oil leak in his power unit before the session got underway, which forced his mechanics to change to the older spec unit.
Despite the small delay, Bottas managed to set the most laps of any driver during the session, clocking 35 laps in the 90-minute session.
Charles Leclerc was fourth in the second Ferrari, heading the Red Bull duo as Max Verstappen finished ahead of teammate Pierre Gasly.
The sausage kerbs placed around the circuit to enforce track limits caused issues for some drivers, as Hamilton and Lance Stroll lost small parts of their cars running over the yellow marked kerbs.
However, Nico Hulkenberg suffered the most in the final minutes of the session when he ran over the kerbs at the exit of the penultimate corner, which sheared off the left side of his front wing.
The problems are likely to cause a debate from the teams and drivers, some of which may see the kerbs as excessively dangerous.
The midfield fight was a close affair in France, and it is a battle set to resume this weekend in Austria.
McLaren ended the opening practice session as 'best of the rest' with Carlos Sainz, who will take a grid penalty for Sunday's race, was seventh fastest.
Four tenths behind the Spaniard was Daniel Ricciardo in the Renault and the Haas of Kevin Magnussen, while Lando Norris rounded out the top ten.
Alfa Romeo and Racing Point look once again to be struggling, as they filled out the latter spaces in the midfield battle, only ahead of Williams who has consistently been the slowest team this year.
Toro Rosso also failed to end the session with a car inside the top ten as Daniil Kvyat and Alexander Albon, the latter of whom will also take a grid penalty, finished in 12th and 13th respectively.