(CNN) -- Marcel Siem held his nerve amid a late charge from Francesco Molinari to take the Open de France -- his first European Tour title for eight years.
The German finished on eight-under-par, one shot better than Molinari who recorded a final-round 64 on Sunday, the lowest score of the week at Le Golf National in Paris.
The Italian was six shots off the pace prior to Sunday's finale and double bogeyed the first hole but went on to make nine birdies.
But Siem held held firm, despite a dropped shot on the 18th, to take his second title on the European Tour, and his first since the 2004 Dunhill Championship.
"I'm so happy. This means a lot to me," Siem told the European Tour's official website after picking up a check for $640,000.
"First, after eight years it doesn't matter what kind of tournament you won; it's huge, because you've got the confidence again.
"Every time I've played consistent golf this year, and there were so many times up there, I couldn't make it. Stupid things happened the whole time.
"It means so much to me to win after that long stretch. It's all about winning in the end and it puts so much pressure every time you don't win and people start talking, you will never win again and stuff like that, so it's very important for me.
"I love this golf course. I always loved it and I love it even more or even better now. I'm super happy."
Molinari hit just 29 shots on his closing nine holes and despite missing out on the title, he was delighted with his form.
"It's been just an unbelievable day really," he said. "I had a really bad start, but two years ago when I finished second here, I doubled the first on the last day.
"From then on, it was just great golf. I had a couple of good breaks and finally a lot of putts going in the hole.
"I was in the moment, in the zone and I wasn't really counting the birdies. The game has been feeling well all week and everything was coming out perfect."
World No. 3 Lee Westwood shot a closing round of 70 to finish 40th a day after an injury scare nearly forced him out of the tournament.
"The leg is fine - it wasn't a problem today," he said, after fears he may have to miss the year's third major, the British Open at Royal Lytham and St. Annes starting on Thursday week.
Meanwhile, the U.S. PGA Tour saw a sixth first-time winner this season when rookie Ted Potter Jr. claimed the Greenbrier Classic title after a playoff on Sunday.
The 28-year-old beat fellow American Troy Kelly with a four-foot birdie putt at the third extra hole to earn a place at the British Open, the FedEx Cup playoffs and next year's Masters.
He also earned a two-year tour exemption plus the financial security of a $1,098,000 windfall as first prize, having shot a second successive six-under 64 to join Kelly on -16 at the end of 72 holes.
"It was just a big relief," said the left-hander, who had missed five successive haflway cuts before the West Virginia tournament.
"All the struggles the last few weeks, knowing that now I've got a couple years to try to improve on my game and win some more tournaments."
U.S. Open champion Webb Simpson had led after three rounds, and held a one-shot advantage going into the final nine holes as he did at the Old White TPC course last year, but he faded to a tie for seventh on -11 after three successive bogeys derailed his challenge.