Formula 3 convert Esteban Gutierrez was fastest for ART on the first day of testing for the new GP3 Series at Paul Ricard.
The Mexican edged out MW Arden's Michael Christensen by 0.037 seconds at the end of the day, with Pablo Sanchez Lopez third for Addax.
"Today was exciting because just looking at the car for a month without driving it was frustrating for me," said Gutierrez.
"Getting to know the car was our main goal of the day, and in the end it was also a good result for us. It is only the first day so we have to keep working.
"I had a good feeling with the car, and really enjoyed the high downforce - it is good for training for GP2. The feeling is also similar with paddle shifts. It is a really enjoyable car to drive."
Formula 2 race winners Kazim Vasiliauskas (Tech 1) and Robert Wickens (Status) completed the top five.
ART's Alexander Rossi had been quickest in the morning session, before slipping to seventh later on, behind Chilton's Max Chilton - one of several GP2, F2 and Formula 3 racers trying out the new series and providing feedback to teams.
GP3 technical boss Didier Perrin was pleased with how the day had unfolded.
"It is inevitable to get a bit nervous before the first test day of a new series," he said.
"However, after the first hour today I was already quite pleased with the way things were going, especially when each of the teams had at least one or two cars on track so quickly into the session.
"Plus, I saw at least six of the young drivers fighting for on track position and overtaking each other in the very first laps of the series' history - this is something I had never seen before."
Pos Driver Team Time 1. Esteban Gutierrez ART 1m20.949s 2. Michael Christensen MW Arden 1m20.986s 3. Pablo Sanchez Lopez Addax 1m21.283s 4. Kazim Vasiliauskas Tech 1 1m21.402s 5. Robert Wickens Status 1m21.644s 6. Max Chilton Carlin 1m21.761s 7. Alexander Rossi ART 1m21.818s 8. Nigel Melker RSC Mucke 1m21.868s 9. Pal Varhaug Jenzer 1m21.994s 10. Luca Foresti Carlin 1m22.021s 11. Renger van der Zande RSC Mucke 1m22.163s 12. Nico Muller Jenzer 1m22.188s 13. Mirko Bortolotti Addax 1m22.240s 14. Rio Haryanto Manor 1m22.259s 15. Dean Stoneman Tech 1 1m22.357s 16. Leonardo Cordeiro MW Arden 1m22.377s 17. Alexander Simms Atech CRS 1m22.542s 18. Luiz Razia Manor 1m22.645s 19. James Jakes Manor 1m22.653s 20. Tobias Hegewald RSC Mucke 1m22.719s 21. Simon Trummer Jenzer 1m23.395s 22. Viktor Jensen Atech CRS 1m23.585s 23. Pedro Nunes ART 1m24.257s 24. Oliver Oakes Addax 1m24.425s 25. Daniel Morad Status 1m24.555s 26. Jim Pla Atech CRS 1m24.740s 27. Ivan Lukashevich Status 1m25.594s 28. Vittorio Ghirelli Atech CRS 1m25.715s 29. Adriano Buzaid Carlin 1m28.317s 30. Doru Sechelariu Tech 1 1m31.996s 31. Miki Monras MW Arden 1m38.504s