Joint-overnight leader Sihwan Kim moved clear at the top after a second-round 69 put him a shot clear at the Saint-Omer Open.
The South Korean had shared top spot with Englishmen Adam Gee and Simon Wakefield yesterday but his rivals both carded one-over rounds of 72 to drop into a tie for third.
Kim, starting at the 10th with eight successive pars before he birdied the 18th and also the eighth and nine - dropping his solitary shot at the par-three second, took advantage to move to six under as conditions became tougher later in the day.
The 23-year-old, playing his first season in Europe, could have been playing in the US Open in California this week but earlier this month he was the unlucky player to miss out in a five-man play-off at Walton Heath.
"I've been having horrendous luck for the last two weeks and I was really gutted to miss out in that play-off," he told europeantour.com.
"So I'm happy that I'm getting a bit luckier this week and if I could do well here it would make up for it a bit.
"It would be nice to get some payback for that one."
Darren Fichardt moved into second place after he too carded a 69 while fellow South African Justin Walters and Italian Andrea Perrino had the best rounds of the day, shooting 68s, to lift themselves into joint-seventh.
Former Ryder Cup player David Howell comfortably made the cut after a second-round 70 left him one over heading into the weekend.
Defending champion Matthew Zions also made the weekend after a 72 left him three over.
