Lewis Hamilton set the fastest time in FP1 with a 1.32.738 and his teammate Valtteri Bottas followed up just 0.069s behind the championship leader.
Ferrari's Charles Leclerc put in the third fastest time of the session coming in a further 0.373s behind with Max Verstappen in fourth and then Sebastian Vettel in fifth - just over a second shy.
However, the tyres proved a talking point as numerous drivers struggled with grip causing graining and flat spot throughout the session.
Ferrari testing a new wing
Vettel led the testing on Ferrari's latest upgrade in the form of a new front wing.
A downward sloping outboard section has been introduced to create greater downforce on the SF90 and increase the airflow over the two front tyres.
The new design also includes a small fin on the outside of the foot plates in an attempt to push the air out past the new cutout on the end plate and around the front tyres.
Mattia Binotto, principal of Ferrari spoke of the changes to the SF90 but said the small evolution to the front wing will not provide an immediate fix to their problems.
"In France, we will have a few small evolutions, elements that represent for us a useful step in defining the direction we will take in developing the car," said Binotto.
"What we will be bringing won't be the solution to our problems, but the technical feedback we get from these evolutions will be important for the next steps we take."
Ferrari has also brought their original front wing to the Paul Ricard track in which Charles Leclerc started FP1 with.
The Pirelli tyres suffered a lot throughout the First Practice session as some of the drivers struggled with graining and flat spots.
Vettel told his Ferrari team that he was unable to do two consecutive laps on the tyres which will prove a concern for the Scuderia team considering they only have nine sets of tyres for the whole weekend.
Red Bull's team boss, Christian Horner said: "I think the fact it's a new surface is quite aggressive. Hopefully, it calms down as it rubbers in and settles down - in that session there was a lot of evolution."
Green track also causing problems
There was a list of drivers struggling to keep their grip throughout the corners - both of the Red Bull's falling victims in the 90 minutes.
Verstappen lost the back-end going into Turn 8, the Dutchman could not keep his RB15 under control but was able to get away with his error despite spinning off the track.
His teammate, Pierre Gasly suffered going into Turn 4 after locking up and sliding sideways - ruining his C4 tyres.
Daniil Kvyat was the first of the drivers to suffer as he oversteered wide in Turn 5 causing some large flat spots on his front tyres.
Romain Grosjean only managed nine laps in his Haas VF-19, after suffering some early problems the Frenchman returned to the garage and watched the rest of FP1 from the pit wall.
First practice result
1. Lewis Hamilton - 1:32.738
2. Valtteri Botttas - 1:32.807
3. Charles Leclerc - 1'33.111
4. Max Verstappen - 1:33.618
5. Sebastian Vettel - 1:33.790
6. Pierre Gasly - 1:34.091
7. Lando Norris - 1:34.110
8. Carlos Sainz - 1'34.261
9. Daniel Ricciardo - 1:34.540
10. Alex Albon - 1:34.804
11. Sergio Perez - 1:34.809
12. Nico Hulkenberg - 1:34.810
13. Lance Stroll - 1:35.063
14. Daniel Kvyat - 1:35.326
15. Kevin Magnussen - 1:35.410
16. Kimi Raikkonen - 1:35.522
17. Antonio Giovinazzi - 1:36.102
18. Nicholas Latifi - 1:37.147
19. Robert Kubica - 1:37.172
20. Romain Grosjean - 1:37.620