Gary Emerson (68) and Peter Hedblom (66) share third place at 12-under-par 132. Lee Westwood, who is searching for his first win since the 2000 World Match Play Championship, carded a 4-under 68 and shares fifth place with Stephen Gallacher (66) at 11-under-par 133.
Karlsson got going on the back nine at Golfclub Mnchen Nord-Eichenried. He got off to a hot start as he eagled the par-5 11th and cruised to the 18th where he rolled home a birdie to head to the front side at minus-10.
On the front side, he caught fire. Karlsson rolled in a birdie at the third and followed with another at the fifth. Karlsson eagled the par-5 sixth for his third eagle of the tournament. That helped him move to 10-under par on the four par-5s over the first two days.
'This course is set up for a long hitter and if you play the par-5s well you have the chance of a good score,' said Karlsson. 'It is easy to get frustrated when everyone else is shooting low scores so you need to stay patient and take chances. I have played the par-5s extremely well, 10-under for the par-5s, which certainly helps your score.'
Karlsson kept rolling with a birdie at the par-4 seventh. However, his momentum was briefly halted when he dropped a shot at the par-3 eighth but Karlsson ended with a flurry as he birdied the ninth, his 18th, to finish two strokes clear of the field.
Jacquelin, who tied the course record of 10-under-par 62 on Thursday, had a steady start before rolling in an eagle at the sixth. He stumbled to a bogey at the next, but capped his front nine with a birdie at the ninth.
Around the turn, Jacquelin birdied the par-5 11th but again lost a shot as he bogeyed the par-4 14th. He closed out his round with a birdie at the par-3 17th.
'It was a good day for me,' Jacquelin said. 'The conditions were a lot more difficult than Thursday. I played the par-5s well except the three-putt on the last. It is always difficult to play after a 62 because you made so many birdies, you expect them like the day before. But you still feel confident and I am looking forward to the weekend.'
Thomas Bjorn, the 2002 champion, leads a group of six players at 10-under-par 134. He is joined there by Charl Schwartzel, Marcel Siem, Paul Casey, Gary Evans and Jose Manuel Lara.
The cut line fell at 3-under-par 141. Among those not advancing to the weekend were former champion John Daly and Nick Faldo.