Kurt Kitayama carded an excellent round of 68 in testing conditions to set the clubhouse target on day two of the Amundi Open de France.
Overnight rain meant Le Golf National was playing longer than on day one and with increased winds and cold weather also in play, conditions were far tougher.
American Kitayama had opened with a 66 and followed that with an arguably more impressive effort, making five birdies and two bogeys to get to eight under.
Overnight leader George Coetzee picked up an early birdie in his second round to sit a shot back having completed two holes, with home favourite Benjamin Hebert and South African Jaco Van Zyl the nearest challengers in the clubhouse at five under.
Kitayama has claimed two victories in his maiden European Tour campaign but his third place finish at last week's Italian Open was his first top ten since winning the Oman Open in March.
He quickly moved into a share of the lead with a birdie on the tenth but gave the shot back on the 12th before taking advantage of the par five 14th.
A wonderful second from the rough at the third allowed him to set up a two putt birdie from the fringe and another excellent second shot to six feet after missing the fairway at the fifth put him two ahead.
A poor tee shot at the eighth brought a bogey but an up-and-down on the ninth meant Kitayama had six birdies from six on the par fives through 36 holes.
Playing partner Hebert also birdied the tenth but his bid looked to be going up in smoke as he sandwiched a double on the 15th with bogeys on the 12th and first.
A birdie on the par five third steadied the ship and 20 footers on the sixth and seventh had the 32-year-old back level on the day.
Van Zyl made birdies on the second, seventh, eighth and 15th in his 70 to go with dropped shots on the fourth, fifth and 12th.
Home hero Victor Perez carded a level par 71, sandwiching bogeys on the 13th and 18th with gains on the tenth and third to sit at four under.
Belgian Thomas Detry, New Zealander Ryan Fox and Finn Kalle Samooja were in the clubhouse five shots off the lead.