Last month I traveled with my friend to Frankfurt with a car, we parked outside a shopping mall to eat for half an hour, and when we came back we found the car is gone. At first we thought the car was stolen but after calling the police for the lost car we realized that we parked in the disabled parking slot.
I didn't take a photo of the sign and it was like the one above, not so obvious and it was right behind another normal parking sign.
And then we spent 2 hours going to pick up the car as they dragged it all the way out of frankfurt from the city centre. I am sure when we go to the company the car is still on the way, because even they took the car immediate after they can't bring it that far. For this "service" the company provided we had to pay 263 euro...
Also there's an extra penalty for the police which is only 40 euros...
It is certainly a good idea to give privilege to people in need.
But somehow I think they removed the car too fast and as a foreigner I didn't even know what was going on. Luckily my friend who drove is a German so he knew what happened. Yet for someone who grew up in Frankfurt would also make this mistake, the tourists would be easily fall for this.
There were a lot of free normal parking slot right next to this one, and honestly i don't see the point why would a company 2 hours away came to the city centre to take the car. Even someone called them they can't be here within half an hour... And the company charges 6 times more than the police fine, it is more like they are just running a business there..