Perez arrived in Germany with good form under his belt, having defeated Ryan Fox in a play-off to win the Dutch Open last Sunday.
The 29-year-old is now on course for another piece of silverware following an impressive third round performance at the Green Eagle Golf Courses.
Perez was on top of his game right from the start of the day, producing a birdie on the first and the hole-in-one on the second.
The player holed out with a six iron from 217 yards as he fired himself into the lead, ahead of playing partner Jordan Smith.
A bogey on the fifth was ratified with a birdie on the ninth as Perez retained his place at the top of the leaderboard. However, bogeys on the 13th and 15th saw the Frenchman fall two shots adrift of Joakim Lagergren.
The Swede, though, had his own issues and suffered a double bogey on the 16th before dropping another shot on the last.
France's Julien Brun looked to take advantage with birdies on the 15th and 16th, however his lead proved short-lived as a double bogey on the 18th put Perez back in the driving seat on five under par.
Brun and Lagergren share second place on four under, with Holland's Wil Besseling and China's Li Haotong on three under, Besseling having holed from 57 feet for an eagle on the 18th.
On a difficult day in Hamburg, Smith's 77 dropped him four shots off the pace, with world number 41 Tommy Fleetwood another stroke back following a 69 - the joint lowest score of the day - which propelled the Ryder Cup star 35 places up the leaderboard.