The 27-year-old joins after leaving SV Hamburg in his homeland and links up with former Hamburg colleague Michael Mancienne at the City Ground.
Mancienne will miss this weekend's trip to Bolton Wanderers after being sent off against Tranmere Rovers in midweek and Stuart Pearce has warned his side that despite two wins in two games they will need to improve to take three points home from the North West.
David Wheater returned to Bolton action after injury as they edged past Bury in the Capital One Cup and is looking forward to playing against a team managed by Pearce who he knows well from England under-21 duty.
"You wanted to do the best for him because he’s an English hero," said Wheater ahead of the game. "When he talks you think ‘oh my God, I hope he doesn’t switch here and go mad,’ he’s got that kind of aura about him.
"He’s good to play under and he’ll definitely get Forest going. It’ll be a tough game."
Loan signing from Cardiff City, striker Joe Mason has received clearance to play for Bolton in the game.