Legal question: Towing a vehicle?

Hi together, I feel a bit wrong here, but there is unfortunately no Laberecke or a topic on legal questions here. Therefore I ask for my own safety times here I moved 4 weeks ago and to my apartment also a private parking space here on the grounds of the residential complex.. For this parking space I pay 40 euros per month. Since I have rented a garage here on the grounds, I do not need the parking space actually. Only if I briefly on the Now it’s the case that the rental place is part of the apartment and I have to pay for it. I have no problem with that, because I use it now and then. For two days now, however, there is a vehicle on the parking space, which is definitely not part of the residential complex. I haven’t found the holder yet. I actually have no problem with it, if someone puts himself on the place for a short time. But after 2 days I find that somehow bold. I have a note to the car with the request to remove it within the next day. Otherwise I have to tow it away. To tow it, I would have the question: Do I have to call the police or how does it work? If I have to dispose of the car privately, I will stay at the expense and have to file a civil complaint with the police about such a car. just annoying – so not on the 110, but under the normal number? So how do I have to proceed? Thank you Karl