Sometimes the law is a strange, abstract and frustrating affair. Just ask a driver from Munich who was involved in an accident and might be able to prove that it wasn't his fault by showing his dashcam video. Yet the judge doesn't want to see it.
In this specific case the accused wanted to turn right onto a street with two traffic lanes in each direction. He waited until the right lane was free, and just as the accused pulled out into traffic a car changed from the left to said right lane and both crashed. Of course the other driver insists that he indicated the lane change and the accused therefor violated his right of way while the accused points to his video which shows the contrary.
The judge however is of the opinion that carrying a camera around to secretly supervise other people without a specific cause violates the fundamental right of informational self-determination. He puts this right above solving cases of civil and criminal law. Thus he wouldn't allow the video as evidence.
And he isn't alone. Only a few days ago an administrative court decided that dashcams infringe information privacy and that it's therefor illegal to publish the videos for example on Youtube or to hand them over to the police as evidence.
The use of dashcams in general is tolerated however since there are grey areas at the moment. You are allowed to use dashcams for example to shoot a holiday video strictly for private use.