Is this parking fine justified - bona fide?

This morning I arrived at my car to see 2 policemen standing there. It was concerning the parking of my car. Arrantly the space was reserved. They pointed out the small signs to me. When I arrived yesterday eve, the space was full of parked cars and the signs had disappeared between the cars. It took the last one parking space, and counted myself lucky....

Anyway when I arrived at my car, one of the police men asked for my ID. He wrote my name on a list. There were already about 8 names on it already, whilst there were 2-3 cars left parked in that space. He then told me that he already had phoned the towing company. I did not see the towing truck and also not one arriving. He said I had to pay for that, plus another fine on top .... I find it strange, I have no proof that he phoned the towing company, if the truck arrives it can only tow one car at a time and there were still cars there to be towed away. So basically he will have about 10 people at least on his list paying for maybe 1 or 2 towing trucks which cost around 100 euro per go. The profit will be 800 euro (!). On top of that the individual fines from the police...

Is this correct????