Paul Waring shot a faultless 64 to take a two-stroke lead after the opening round of the Open de France, but Thomas Pieters stayed in touch at the course that will stage the 2018 Ryder Cup.
Englishman Waring, playing on a medical exemption following a shoulder injury, is seeking a maiden European Tour title, with Pieters among his rivals on a group of three players on five under.
The Belgian made an impressive Ryder Cup debut last year, top scoring for the visitors at Hazeltine with four points, and the world number 28 will welcome a closer look at Le Golf National course, where Europe will attempt to regain the title.
A solitary blemish blotted his copybook, with a bogey six at the ninth leaving him tied for second with Nathan Kimsey and Alexander Bjork, who are seeking qualification for next month's Open Championship.
The top three players who are not otherwise exempt will make it to Royal Birkdale for golf's oldest major.
Other notable names to have broken par in fair conditions were Tommy Fleetwood, who finished fourth at the U.S. Open and shot 67, Spanish youngster Jon Rahm, who signed for a 70, and the two-under-par Alex Noren.