What is the rule at this traffic-light-controlled junction with additional signage?

The sign indicates that cyclists are allowed to turn right at the red traffic light. This is a special rule in German traffic regulations where, if a supplementary sign shows a green arrow with a bicycle icon under a red light, cyclists may proceed to turn right after stopping and yielding to pedestrians and other traffic.

Motor vehicles, however, must still wait for the green light and are not allowed to turn right on red unless there is a specific sign allowing it for motor vehicles.

This rule helps to facilitate smoother and safer bicycle traffic flow at intersections while maintaining safety for all road users.