@Andrea5073 Of course he doesn't have the right to scam people. Are you under the impression that the hosts who have responded here are condoning his behavior? Of course not- bad hosts reflect poorly on the platform and that affects all the good hosts, too. Most hosts would like to see scamming hosts kicked off the platform.
We said it's probably not worth your while to approach him about it because as you describe him, he's not going to then refund you the difference, he's just likely going to respond unprofessionally or even belligerently, and then leave you a bad review.
But as I said previously, if it feels to you like you should let him know that you are aware of his scam, that's up to you. If I were in your shoes, I would just wait and mention it in the public review you leave, to warn future guests, which might be more worthwhile. That might force his hand to list the real tax, not an inflated one, and you will have publicly shamed him and alerted other guests. I think that might allow you to feel like you haven't just "accepted" it, and will have more impact than him even giving you back your few euros and continuing to overcharge future, unsuspecting guests.