Defending champion Graeme McDowell was six shots off leader Kevin Stadler after a round of 70 of the French Open

Stadler said all the right things after carding a flawless 64 to claim the lead after the opening round of the Alstom Open de France at Le Golf National.

Masters champion Bubba Watson created a poor impression of Americans abroad after playing the tournament in 2011, describing the Eiffel Tower as "that big tower", the Louvre as the "building starting with an L", the Arc de Triomphe as "this arch I drove round in a circle" and the Versailles Palace as "the castle we're staying next to" during his brief trip.

But Stadler staged something of a charm offensive after carding seven birdies and no bogeys to lead by one from Germany's Marcel Siem, with Scotland's Stephen Gallacher a shot further back on five under.

Damien McGrane (level), Peter Lawrie (+1), Gareth Maybin (+2), David Hoey (+2), Padraig Harrington (+3), Kevin Phelan (+5), Simon Thornton (+6) and David Higgins (+8) are also in action. 

"It's one of my best rounds of the year for sure"

"It's one of my best rounds of the year for sure," said Stadler, who won his maiden PGA Tour title in the Phoenix Open in February and was half of the first father-son pairing to play in the same Masters with his father Craig in April.

"To not make a bogey out there is something I didn't think was possible when I first played it. It's instantly one of my favourite courses ever, I thought it was spectacular from hole one to the end. They talk about the last four holes but they are doing a discredit to the previous 14.

"I have always wanted to come over here, the guys in the US tell me it's one of the best events of the year and it has not let me down. It has been fantastic."

Ryder Cup hopeful Gallacher was left to rue a poor finish despite carding an opening 66, the Scot looking 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.

However, 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.

Gallacher is currently outside the automatic qualifying places for September's 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 Dubliner pulling out of the event with a shoulder injury.

"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," Gallacher said. "I'll still take two (shots) better than my previous best in this event."

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."

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 thanks to a hat-trick of birdies from the sixth.

"I always enjoy coming back here, I love the track and had a good start this morning," Siem told Sky Sports. "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."

US Open champion Martin Kaymer recovered from dropping three shots in his first two holes to card a 72.