The next-generation GP3 car had its first test sessions last week, the series has revealed.
Ex-GP2 racer Ben Hanley gave the car a shakedown at Italian circuit Varano, before the car was taken to Magny-Cours for two days of running.
The new car has switched from a turbo to a normally-aspirated engine, and GP2/GP3 technical director Didier Perrin explained that the aim of the first tests was to focus on that area.
"The purpose of the test in Magny-Cours was to develop the strategy for making the engine and gearbox work together," said Perrin. "In this early stage of development, engine and gearbox management is key.
"The next test will focus on the performance of the car, so the next step is to work on the aerodynamic settings. We need to check that the data from the Dallara windtunnel corresponds with live on-track data."
Hanley added that he was impressed with the car, which will be revealed to the public at the Italian Grand Prix-supporting season finale in September.
"There is quite a big power increase with the engine upgrading to a V6," said the Briton. "The sound of the car is a massive improvement; I really noticed it while driving.
"The car is much more demanding to drive, you have to drive on the edge and I think it's a lot more fun to race with the GP3/13. Visually the car is much nicer to look at too. It will definitely raise the level of the series."