Jesper Svensson made a late surge into a share of the lead in round one of the 2024 FedEx Open de France.
The Swede birdied four holes in a row at Le Golf National before a closing par left him alongside early leaders Thorbjørn Olesen and Joe Dean on six under par.
Amateur Lev Grinberg was the eye-catching name in a group of five players one shot off the lead at five under.
Englishman Dean, who made three eagles on his way to a tie for third at last month's acciona Open de España presented by Madrid, was back in the same groove with a perfect approach to the par-five third in France.
Two birdies in the remainder of his front nine and two more in the final four holes saw him to an unblemished 65 - alongside Olesen, who birdied the first four holes and seven in all before a lone bogey at the 15th.
The Dane said: "On the first, I holed a really long putt for birdie and then the next three I hit them pretty close. Obviously three is a par-five you can reach.
"With the soft conditions, there's definitely a lot of chances out there.
"(It asks) a lot of questions of you but if you are really on your game, you have a lot of birdie chances. I think it's just a great golf course and I really enjoy playing here."
Svensson made a flying start with three birdies in the first five holes, going within three feet of a hole-in-one at the second, but then had to be patient around the turn.
He bogeyed the 13th but responded in style, hitting his approaches close at the next two to set up birdies and then holing from 43 feet at the 16th before another nerveless putt at the next took him alongside Dean and Olesen.
He said: "Good start today, definitely. Two good shots and set up some nice putts. (Then on the closing stretch) it was nice, I had some good putts rolling in."
Home hope Adrien Saddier looked set to join the leading trio after a superb approach to three feet at the last but the putt stayed up and he signed for a 66.
Saddier birdied the second, third and fourth holes, with his only bogey coming at the ninth before further gains on a pair of par-threes, the 11th and 16th, as well as the par-five 14th.
Grinberg, the 16-year-old Ukrainian, is living in dormitories at Le Golf National while he works with the French Golf Federation Academy to develop his game, and it paid off with two separate runs of three straight birdies in his 66.
He was joined at five under by his German playing partner Yannik Paul, Saddier, Paraguay's Fabrizio Zanotti and Dane Nicolai Højgaard.
The latter was two under after a birdie at the sixth but gave both shots back over the next two holes before a remarkable approach to the ninth kick-started his round.
In deep rough just short of one bunker and with another in his path to the green, Højgaard hammered a low shot into the bank in front of the green which kicked up to set up a 17-foot putt for a third birdie.
Four more on the back nine, the pick of them a 27-foot right-to-left putt at the 17th, saw him to a 66. Twin brother Rasmus was on a similar track for much of the day but a bogey at the last dropped him to three under.
England's Justin Rose was among a large group at four under alongside compatriot Dan Bradbury, South African trio Brandon Stone, Dylan Frittelli and Justin Harding, home favourite Clement Sordet, China's Haotong Li, Lukas Nemecz of Austria and Swede Marcus Kinhult.
