Eintracht Frankfurt have made two further signings, with Erik Durm and Dominik Kohr arriving from Huddersfield Town and Bayer 04 Leverkusen respectively.
Durm joins on a four-year deal following his contract expiring at the Yorkshire club.
Kohr is signed until 2024, with an estimated fee of €10 million.
Durm returns to Germany
The 27-year old made 28 appearances in his one season in England for Huddersfield. After experiencing relegation with The Terriers, Durm was keen for a move back home.
After being a member of the 2014 World Cup-winning squad, the full-back will hope to get his career back on track and push for a place in the national squad once again.
Eintracht Sporting Director Fredi Bobic is hopeful of the player's impact.
"It's great that we have been able to sign a seven-time German international and 2014 World Champion," he told the Frankfurt website.
"Erik Durm not only expands our possibilities, but he is a strong character and an outstanding team player. Erik has played at the highest level nationally and internationally, these experiences are a great added value for our team."
Kohr added to ranks
Only hours after the move for Durm was sealed, Bobic completed the signing of Kohr.
"Dominik Kohr is a real asset to our game and the fact that German players at this level come to us is proof of the positive development of Eintracht Frankfurt over the last few years, and it suits us best for our style of play and character," Bobic told Sky.
The signing of the player signals a statement of intent from Eintracht. Kohr still had two years left to run on his Leverkusen contract, yet the club were willing to pay for his services to prise the midfielder away from a rival.
That Frankfurt are able to buy from and compete alongside seasoned European campaigners such as Leverkusen is a testament to the progress of the side in the past few years.
At 25, Kohr still harbours potential. To date, he has made 145 Bundesliga appearances. Kohr will hope of more regular game time in the Eintracht midfield than he got at Leverkusen, where he fell out of favour under new Head Coach Peter Bosz.
Continuation of Bobic's transfer policy
The strides made by Eintracht in recent seasons can largely be attributed to the Sporting Director. Last season saw the club reach a Europa League semi-final and challenge for the top four in the Bundesliga.
Earlier in the window, Frankfurt signed young prospects Dejan Joveljic and Djibril Sow. Bobic will hope the signings of Durm and Kohr further improve the squad and help continue the steady progression that the club has made in recent years.