@Maryam80
Maryam there are many local authorities around the world that require the payment of a 'lodging tax' from hosts who rent a part, or the whole, of their property to guests. In most of these Airbnb will have set up an agreement with the local authority to collect tax on behalf of the host. They will deduct the tax from the hosts payout figure, but this amount will have been factored into the hosts nightly rental. In some instances this arrangement has not been put in place, and it is solely up to the host to collect the required tax from the guest on arrival, and forward it to the local authority.
I know it is terribly annoying but, it can be legitimate, and it's not the hosts fault! The host is not being greedy or underhand.....the host is just doing what is required of him by local laws!
https://www.telegraph.co.uk/news/2018/12/31/venice-introduce-visitor-tax-latest-bid-manage-impact-ma...
Maryam, blame the government, not the host or Airbnb....we just work to rules!
Cheers.......Rob