I have done a few searches and it seems to be that some pay it and some don’t, so I would suggest you contact your town hall, probably only they can give you a substantive answer for that municipality. .
I would not think that an owner of a park would lie about such a thing as that would amount to a very easily provable criminal offence.
If the law has been changed as you have been told, I don’t see that as a bad or outrageous decision. People living in any permanent home pay whether they own or rent.
The law is often hard to understand. Example: In USA so called mobile homes (RV’s) on private land, parks etc. which are bricked into place, very permanently, with flower beds, plumber water and sewage etc. have to pay the State number plate renewal registration tax (Road tax) every year.