I'm an Italian girl who works in London.
My mother was born in Croatia and she moved in Italy when she got in married with my father, an Italian man.
She has both citizenships and, currently, she is resident in Italy. She is 70 years old and she is retired.
She has got a property in Croatia and she was thinking to rent it.
For this reason, my mother has registered her property as a holiday home onto the local council's list and she pays an annual tax because that.
Until now she couldn't rented the house. I suggested her to use Airbnb to start to rent the property.
Can she rent a property in Croatia through Airbnb if she is resident in Italy?
If yes, does she have to pay a tax in both countries and what taxes?
Is there a tax-free allowances?
Yes your mother can rent out her home if local laws say that there can be short term lets in the area (some places she will need a license).
She will need to speak to an accountant about her tax situation.
You can help her by researching what other sorts of properties are listed locally, what facilities they have, how they market the property and making sure she has quality photos. And if she goes ahead to set up the listing. If she doesn't want to manage guest inquiries you could do this for her.
She/you will also need to find a local manager to help manager cleaners and change of towels/linen and to help should any problem occur with guests or maintenance such as shower going wrong. This could be done by a local co-host (see Airbnb Help Centre) or a local airbnb management company.
Managing a property remotely via Airbnb can take quite a lot of work.
She might be better just finding a local company who can do weekly holiday lets for her (or multiples thereof).