About The real hierarchy: who overrules whom on priority?: which statement is WRONG?
The order is: traffic controller, then traffic lights, then signs, then the rules; a controller who is present overrides the signs.
If the traffic light is green, you may ignore every other sign at the junction, including signs that have nothing to do with priority.
Instructions from an authorised officer or traffic controller override traffic lights, which in turn override signs.
Traffic signs are used precisely WHEN the traffic rules (such as the rechts-regel) are not sufficient.
Explanation
trap: light-supremacy over-applied. Traffic lights override signs THAT REGULATE PRIORITY, not every sign in general. A sign regulating something else (speed, parking) simply remains in force alongside a green light