Derrick Kohn is looking forward to bringing his "qualities" to Union Berlin after sealing his move from Turkish giants Galatasaray where he won the Super Lig title.
Turkish referee Halil Umut Meler has left hospital after being treated for injuries suffered in an attack at the end of a Super Lig game on Monday.
Domestic football in Turkey has been suspended indefinitely after one of the country's top referees was punched to the ground by a club president following a Super Lig match on Monday.