Kaymer overcame a painful blister and a bogey on his first hole with eight birdies and an eagle on No. 3 to tie the record set by Eduardo Romero of Argentina in 2005 on the 7,300-yard Golf National course.
My putting was pretty good today, said the 24-year-old German, who started at No. 10. That kept my score low.
The 2007 European Tour Rookie of the Year had cut a hole in his right shoe on Wednesday to relieve pressure on the blister and play in the Pro-Am.
I had a big blister yesterday, he said. Today, its still hurting a little bit but I was surviving.
Thongchai Jaidee of Thailand, Rafa Echenique of Argentina, Scott Strange of Australia, Peter Hanson of Sweden and John Bickerton of England all shot 65s.
It was nice to have a good day out there for a change, said Bickerton, the 2006 French Open champion. The fairways are tight here, but if you do get the ball in the right places then you can get the ball close to the hole and the greens are quite receptive.
Englands Paul Waring had a share of second place until he dropped a shot on the 17th and finished with a 66. Countryman Nick Dougherty, who won the BMW International Open on Sunday, also had a 66 after a birdie on his final hole.
Its lovely to kick off again with another good round on the back of winning a golf tournament. Its not always easy to do, Dougherty said. My short game was super. Ive become a lot more consistent around the green.
Kaymer collected two titles and three runner-up finishes in 2008, but has been struggling lately, missing the cut in his last two starts. That poor run of form changed with four birdies on his first nine holes, another at No. 1 and then the eagle on No. 3. He finished with birdies on Nos. 7-9.
Ian Poulter of England (72) and three-time major winner Padraig Harrington of Ireland (72) were among the players who didnt find the course so accommodating.
Its not great for this weeks tournament because I am 10 shots behind, but I was encouraged by the way I played, Harrington said. The putting green is very slow and I am struggling a bit with the pace of the greens.
Masters winner Angel Cabrera of Argentina had a 75, while European Ryder Cup captain Colin Montgomerie stayed in the running with a 69.
Miguel Angel Jimenez of Spain had a 67 for a share of ninth place with 10 other players including fellow Spaniard Pablo Larrazabal, the defending champion.
Jimenez received a silver ice bucket after his final hole to celebrate his 500th appearance on the European Tour.
Golf is my life and has given me everything, the 45-year-old Jimenez said. To play 500 tournaments is a great achievement and makes me proud.