By Tobias Carroll What makes for a great movie about a city? That subject alone has itself led to some memorable onscreen work — notably, the 2003 documentary Los Angeles Plays Itself. But finding the right approach to convey the essence of a city (or, perhaps, a neighborhood within that city) to a viewer who’s never set foot in there can be a challenge for even the most talented filmmaker. One actor who’s appeared in a host of great films about cities is Robert De Niro. And in a new essay for Deadline, he made the case for Paolo Sorrentino’s The Hand of God as being particularly effective and…