Foreign (non-EU) investment in the exploration and exploitation of liquid and gaseous hydrocarbons is subject to a reciprocity requirement
"TITLE II - HYDROCARBONS AND GEOTHERMAL
CHAPTER I - RESEARCH AND CULTIVATION OF LIQUID AND GASEOUS HYDROCARBONS ON THE LAND IN THE TERRITORIAL SEA AND ON THE CONTINENTAL PLATFORM
Art. 3. (Prospecting permit). 
1. The prospecting permit is granted upon request by submit to the Ministry of Industry, Trade e crafts, to natural or legal persons who have adequate technical and economic skills. ((2)) 
2. The prospecting permit is granted to Italian or Italian subjects other member states of the European Economic Community, as well as, a conditions of reciprocity, to subjects from other countries. 
[...]
Art. 5. (Research permit and qualifications of applicants). [...]
2. The research permit is granted to Italian or other subjects Member States of the European Economic Community, as well as, under conditions of reciprocity, to subjects from other countries. 
[...]
Art. 9. (Cultivation concession. General provisions). 
1. To the permit holder who, following the drilling of one or more wells, has found liquid or gaseous hydrocarbons and granted the concession of cultivation if the production capacity of wells and other elements of geo-mining evaluation available technically and economically justify development of the discovered deposit. [...]" (LAW of 9 January 1991, n. 9, "Rules for the implementation of the new National Energy Plan: institutional aspects, hydroelectric power plants and power lines, hydrocarbons and geothermal energy, self-generation and tax provisions"; last amended by DECREE-LAW 18 October 2012, n. 179; Articles 3, 5 and 9 [google translation])
LAW of 9 January 1991, n. 9, "Rules for the implementation of the new National Energy Plan: institutional aspects, hydroelectric power plants and power lines, hydrocarbons and geothermal energy, self-generation and tax provisions"; last amended by DECREE-LAW 18 October 2012, n. 179; Articles 3, 5 and 9
[<a href="http://www.normattiva.it/uri-res/N2Ls?urn:nir:stato:legge:1991-01-09;9!vig=2021-08-19">Law</a>]