The Mahindra team has had at least one if not both riders in the top-ten of every race so far, with a best of fifth for Oliveira at Austin in Texas.
Fighting for top positions on a tricky wet-and-dry Le Mans circuit, Oliveira fought hard in a tight-packed group of six disputing the lead on the fourth of 24 laps of the 4.185-km Bugatti circuit at Le Mans.
Second rider Efren V�zquez did not start, returning to Spain for surgery after suffering a fractured collar-bone in a crash in free practice.
The race was won by Spanish KTM rider Maverick Vinales. The next round is the Italian Grand Prix at Mugello in two weeks.
"Another rider tried to pass me on the straight, so I moved a little to the outside. It seems it was not a good idea - it must have been a bit damp. I lost grip on the front and slid off. Overall though it was a good weekend, and we made a step forward. Now we must think of Mugello, and if we can keep running like this we are making good progress," Oliveira said.