@Peter1598
If you are renting in Italy, you will have to specify in your ad that at check-in guests will have to draw up a lease agreement, even if that lease agreement lasts only one night. The stipulation of a rental contract in written form is also necessary when the meeting between host and guest is done by AIRBNB or other portals.
For periods longer than 30 days the concluded rental contract must be duly registered in the tax authority (Agenzia delle Entrate).
In some Regions and Provinces in Italy, it is forbidden for those who rent to tourists to advertise on AIRBNB and other portals: the financial police (Guardia di Finanza) might think you’re an entrepreneur, especially if you do not sign a rental contract.
You will have to send personal data of your guests (including minors or infants) through the web portal of the State Police (https://alloggiatiweb.poliziadistato.it/PortaleAlloggiati/), but only for short term lease contracts of less than 30 days.
The credentials (user/password) for the connection to the Police website are provided to you by the Police only after having presented the documentation of the beginning of your activity to the Municipality.
For long term lease contracts of more than 30 days, the obligation to notify Police is absorbed by the registration of the lease contract, unless the guests are non-EU citizens: in this case, you will have to notify Police through the form "Communication for hospitality" (Comunicazione di ospitalità).