CANNES, France — We caught Sohrab Mirmont at the World Women Foundation in Cannes on May 12, fresh off a panel and about to start shooting his new film in Venice. He is the nephew of Abbas Kiarostami, the Iranian maestro who won the Palme d’Or in 1997 for “Taste of Cherry” and the Venice Grand Jury Prize in 1999 for “The Wind Will Carry Us”, and who shot “Certified Copy” in Tuscany. Sohrab, who produced “Riddle of Fire” on Super 16mm outside the Hollywood system, has signed Luca Bigazzi, his uncle’s cinematographer on “Certified Copy”, and Italian actor Riccardo Scamarcio in what he promises will be one of the actor’s deepest performances yet. The story, half Italian and half English, was born on a water taxi gliding through the canals.