Sweden's Christian Nilsson, without a single top 35 finish all season, was the leader of the Alstom Open de France after the first round at Le Golf National near Paris.
The former St Omer winner shot a six under par 65 on the course that will host the 2018 Ryder Cup.
The 33 year old, 263rd in the Official World Golf Ranking, leads by one from England's Gary Boyd, Italian teenager Matteo Manassero and ISPS Handa Wales Open winner Thongchai Jaidee, from Thailand.
World Number Three Lee Westwood recovered from four over after six holes and from playing one shot while standing in a lake to match Open Champion Darren Clarke's 70.
Nilsson said: "It's been a struggle for me so far this year. My long game was pretty bad, but it's improved and this is good for my confidence.
“I've been very patient I think. I've been practising on things I believe in and just waiting for something to happen - finally looks like it did.”
He followed four birdies in six holes with a bogey six at the 596 yard ninth, then collected more birdies on the tenth, 14th and 15th.
It is only just over a month ago that Boyd began with an 88 that included two tens at The Celtic Manor Resort, but he flew to America to see his coach straight afterwards and has put the pieces back together.
"That was a bit of a disaster, but I've had a lot of positive signs the last three weeks," said the 25 year old, twice a runner-up since stepping up from The Challenge Tour two years ago.
"I'm working on the right things I feel and am getting comfortable again. My game wasn't where it needed to be and it was time to take a time-out."
Manassero, who already has two European Tour wins to his name, also had five birdies and no dropped shots.
“It was a very good round,” he said. “Everything was going the right direction, the way I wanted.
“You have to give yourself the most opportunities for birdies that you can, and I didn't feel like I putted that well, but I was solid and I made some of those chances.”
Westwood, in his last tournament before The Open Championship, said: "I didn't do much wrong to be four over, but there's not a lot of panic in me any more - I haven't got much time for that.
"It was not going my way, but you just have to get it out of your mind."
His water adventure came on the ninth, his final hole. The ball stopped on the edge, but to play his second he rolled up his trouser legs and waded in with his shoes and socks on.
The reason for not going barefoot was that he remembered Thomas Levet jumping in the lake and breaking his leg after winning last year.
"I didn't know what was in there," said Westwood. "I've got plenty of shoes with me."
His paddle brought back memories of Jean Van de Velde at Carnoustie 13 years ago – and the Frenchman is now the tournament director here.
Clarke, who made his first cut of the year at Royal Portrush last Friday, mixed five birdies - two of them in the dangerous last three holes - with two bogey sixes and a double bogey six on the 399 yard 15th.