The British driver tested the new engine and race set up solutions, completing 70 laps of the French circuit.
“I'm very satisfied with the speed and performance of the car and the steps forward that have been taken since our long test in August," Thompson said.
"I think we have worked very hard with our LADA Granta to maximise its strengths and minimise any weak points.
"In particular we focused on the chassis balance and speed on the long straights, and moved a step forward compared to the car we had one year ago. It is quite important, as the championship visits many high speed circuits.
"This updated variant of the car gives hopes for better overall performance, especially in the race. Now we should focus on further improvements and I am eager to test new evolutions of the Granta."
Team principal Victor Shapovalov echoed: “It was important to estimate the performance of the car after all the improvements we made. The car was seriously developed in terms of aerodynamics, speed, drivability. James’ feedback is crucial for us to understand in which areas we need some more improvement.”
The LADA Sport Lukoil team will test again at Magny-Cours from February 25 to 28, when Thompson will be joined by his new team-mate and Aleksei Dudukalo.