The StVO § 37 prescribes:
"(1.) Red declares:" Stop in front of the intersection. "After stopping the turn to the right is also allowed in red, if a sign with green arrow on a black background (green arrow) attached to the right of the red light The driver must only turn on the right-hand lane and must behave in such a way as to preclude the obstruction or endangerment of other road users, in particular pedestrian and vehicular traffic in the cleared traffic direction. (...) "