Having raided the Bundesliga for Pierre-Emerick Aubameyang, 28, and Sead Kolasinac, 26, last season, and this week for Borussia Dortmund centre-back Sokratis Papastathopoulos, 29, the Gunners are returning to Germany for RB Leipzig defender Lukas Klostermann.
The 22-year-old is the second Leipzig player targeted by a Premier League club. Naby Keita, 23, is moving to Liverpool in a deal agreed last summer.
Klostermann moved to Leipzig in 2014 for a €1m from Bochum and is under contract until 2021. Last season, he featured at right-back but Emery is keen to bring on board his versatility.
Stephan Lichtsteiner, 34, moved to north London on a free transfer to bring experience and leadership to the squad.
Having been scouted by the Gunners and their bitter rivals Tottenham Hotspur at the start of 2016-17, Klostermann suffered a season of injury, making just one appearance. Last season, he returned to first-team action featuring 28 times.
As well as 12 Under-21 caps, he was a member of the 2016 Olympics team which won the silver medal in Rio. Klostermann scored one goal during the tournament, breaking the deadlock in the 2 – 0 semi-final win over Nigeria.