Gomorrah won the Grand Prix at Cannes this year. It's adapted from a book by Roberto Saviano depicting tales of the society created by the Neapolitan mafia. The book was largely based on true stories, the publication of which sent Saviano into hiding. Read the reviews and be forewarned it has the potential to be disturbingly violent in places and disturbingly nonviolent in others.
If you plan on going I'd advise buying tickets in advance either in person or online. Seating is unallocated so please be there early so we can grab proximity positions.