Defending champion Thomas Bjorn heads a group of four players tied for second two shots behind Jacquelin. Bjorn is tied with David Howell, Gary Emerson and Marcel Siem at 8-under-par 64.
Jacquelin cruised through a bogey-free round at Golfclub Mnchen Nord- Eichenried. He began on the back nine and quickly ran off three straight birdies from the 11th to get off to a hot start.
He added back-to-back birdies from the 15th before rolling home his sixth birdie of the side at the 18th.
On the front nine, Jacquelin again drained back-to-back birdies from the third to move to minus-8, where he joined Bjorn and Siem, who had both completed their rounds.
Jacquelin moved ahead with a birdie at No. 6. He extended his lead to two strokes with a birdie at the par-4 ninth. His 10-under round tied the course record first set in 1989 by David Feherty and later tied six times.
'I played great, of course,' said Jacquelin, who is still searching for his first European Tour win. 'I just tried to be confident on every shot as I am hitting the ball very well at the moment. It is all about confidence. I tried to really concentrate on that and it worked. I hit all the par-5s in two except the ninth which helped.'
Bjorn also got going on the back nine, but did not fare as well on the side as Jacquelin did. Bjorn managed just a birdie on the 18th to make the turn at minus-1.
Around the turn, Bjorn burst up the leaderboard. He rolled home back-to-back birdies from the third and birdied the par-4 fifth to climb to 4-under. That began a run of five straight birdies that moved him into second place.
'I was getting a bit frustrated over the first few holes but my caddie told me to stay patient as you can easily birdie five holes in a row on this course, and that was exactly what I did to finish,' said Bjorn, who also won here in 2000. 'The last nine holes were very, very good. I haven't hit the ball as well as that since the Open. When you shoot 29 you have to be happy. This is a good start and gives you an opportunity for the rest of the week.'
Siem birdied four of the five par-4s on the back nine and also birdied the par-5 18th to open his round. Around the turn, he drained birdies on three of four holes from the fourth to grab a share of second.
Siem used his local knowledge to his advantage. He was a member at Golfclub Mnchen Nord-Eichenried for five years and won the club championship before turning pro.
Emerson, who was in the last group to tee off the back nine, had a similar round to Bjorn. He birdied the 18th, his first birdie of the day, before catching fire around the turn.
He managed back-to-back birdies from the first. Emerson also birdied the fifth before an eagle on No. 6. He then closed out his round with consecutive birdies from the eighth.
Howell notched three birdies over the first six holes. He ran off four straight birdies around the turn, starting at the par-3 eighth. Howell stumbled with bogeys on the 12th and 14th, but mixed a birdie in between at the 13th. He closed out his round with birdies on Nos. 16 and 18.
Robert Karlsson, Paul Casey and Lee Westwood share sixth place at 7-under- par 65. Peter Hedblom, Martin Maritz, Gary Evans, Fredrik Andersson and Ian Poulter are tied one stroke back at minus-6.