"The legal status of foreigners is regulated by law in conformity with international norms and treaties" Art. 10 paragraph 2 of the Italian Constitution. The legal status of foreigners residing in Italy is protected by the provision of enhanced reserve law: the legal treatment to which it is subjected is not left to the whims of the public administration, but it can only be fixed by law and may not be less favorable than as provided in the rules of international law, both customary, both pactional. The legal reserve is not absolute: it admits the existence of lower source legislation and even regional legislation, provided they do not conflict with the rule of law and international law.
The legislative text of the main reference on the subject is the legislative decree 25 July 1998, n. 286 as amended, by breaking D.L. February 18, 2015, n. 7, converted with amendments by Law 17 April 2015, n. 43 and by Law 29 July 2015, n. 115, known as the "Consolidated text of provisions governing immigration and the status of aliens"