Marcel Siem made the perfect start in his bid to reclaim the Alstom Open de France at Le Golf National.
Some sizzling iron shots led to a hat-trick of birdies from the sixth as the 2012 winner carded a six under par 65 to lead Stephen Gallacher by one.
Ryder Cup hopeful Gallacher was left to rue a poor finish despite carding an opening 66, the Scot having looked set to challenge the course record of 62 when he covered his first 14 holes in seven under par and then hit a superb approach to five feet on the sixth.
But the World Number 37 missed that birdie opportunity and then dropped shots on the seventh and ninth, after missing the green with his approach each time.
Siem was in the group ahead of Gallacher and experienced starkly contrasting fortunes on the closing stretch, playing his final four holes in five shots fewer.
"I always enjoy coming back here, I love the track and had a good start this morning," said Siem.
"The putts finally started dropping, last week my putting was horrible, so I am really pleased."
Siem's wife gave birth to their second child last week and the 33 year old German admitted he was feeling the effects of coping with his enlarged family.
"I was really tired," added the 2012 champion, who overcame a dreaded "shank" on the second hole and also bogeyed the 18th after finding water with his approach.
"I can't wait to go to bed. I said that to my caddie on the third hole, I need to get my batteries loaded up."
Gallacher is currently outside the automatic qualifying places for September's Ryder Cup contest at Gleneagles, which is just 35 miles from his home in Linlithgow.
But he will not get the chance to impress European Captain Paul McGinley in person this week, the Irishman pulling out of the event with a shoulder injury.
Despite the poor finish, Gallacher's 66 was still his lowest score in 16 appearances in the event by two shots.
He said: "I missed a putt to go eight under and didn't do too much wrong on the last couple of holes, but that's what this course can do. I'll still take two better than my best."
Speaking about Ryder Cup qualification and the run of big-money events coming up, Gallacher added: "It's a massive run. The thing I have to try to do is play my golf and not think about it really.
"I'm trying not to be too outcome-orientated, just think of what I'm doing on the course and hopefully it's good enough."