'It is a great weekend for golf, a great weekend for me and a great weekend for France,' said Remesy. 'After a major I cannot win bigger for me because the pressure was unbelievable. It is fantastic for myself and for the people who support me.'
Richard Green struggled to a 4-over 75 to finish seven shots back in a tie for second. Green was joined by fellow Australian Nick O'Hern, who shot a 68, at 5-under-par 279.
Remesy carried a three-shot lead into the final round at Le Golf National and seemed to be headed downhill with a double bogey at the opening hole after finding the bushes. Remesy responded and converted a birdie putt from just off the fringe at the second, but gave that shot back with a bogey at the very next hole.
Luckily for Remesy, Green also found trouble on the first hole with a bogey but sank a 5-foot putt for a a birdie at the par-5 third to move within one of the lead.
Remesy recovered from the early struggles and parred his next five holes before his approach to the par-4 ninth stopped within a foot of the hole. He tapped in for a birdie, but Green matched him with a birdie of his own at the ninth to remain one shot back.
Green hit his drive in a hazard at the 10th, however, and scrambled to a bogey to fall two off the pace. Remesy remained steady while Green continued to fall apart on the inward half.
At the par-3 16th, Remesy hit his tee shot to three feet and drained the putt to reach 12 under. The 40-year-old maintained his composure on the closing holes as the local galleries cheered his every shot.
'The crowds were fantastic,' he said.
Remesy sent his drive into the high grass on the 18th tee. He hit out of the rough, advancing his ball down the fairway, ultimately leaving himself with a 9-foot putt for par. Remesy made it, and soon after was drenched in champagne before being tossed in the water off the 18th green.
'The reaction is unbelievable,' Remesy said. 'This is what I work for, for that moment in golf.'
Green, who had his fair share of trouble down the stretch, was in the water to the back of the putting surface with his second. He ended up with a double bogey that cost him second place alone.
Graeme McDowell fired a 7-under 64 to move from a tie for 30th into a tie for fourth along with Jonathan Lomas at 3-under-par 281. Ian Woosnam, who shared the 36-hole lead with Remesy, was one shot further back at 2-under- par 282.
Miguel Angel Jimenez, a three-time winner on the European Tour this season, posted a 69 to join Marcel Siem in a tie for eighth at even-par 284.
Paul Casey, Soren Hansen, David Lynn and Darren Fichardt followed at 1-over- par 285.