Inviting friends and relatives from Non-EU countries
Da Trento Wiki.
In practice you need to do the following steps:
1. If your friends/relatives stay with you - within 48 hours you must go to Questura di Trento with your friends and make "Cessione Fabbricata" (form available here). To do this, you need to fill one form per each person, in two copies, and attach X copies of your ID card/passport (X is the number of guests) and one copy of document of each of people you invited.
2. If they came to Italy from another Schenghen country (e.g., making a change in Munich, or renting a car in Austria) then within 8 working days you must go to CINFORMI and make Dichiarazione di presenza. You just need a document of each people visiting you for this. More info at .
In theory, according to the law (see the last page of Cessione Fabbricata form for explanations) you need to do step 1 only if your visitors stay for 30 days. However, Questura di Trento and CINFORMI both say you need to do Cessione Fabbricata for whatever period.