The art world is about to get a thorough investigation. British ex-pat sculptor Anthony James was inspired to pick up a camera by a friend in LA — German ex-pat director Werner Herzog — and plans to interview 100 artists, dealers, curators and collectors, beginning next month at the Cannes Film Festival. “There’s a lot of crossover between artists and actors and filmmakers,” James told The Post’s Richard Johnson. Producing the doc is Katja Eichinger, who’s also producing one of Herzog’s next movies, an adaptation of DBC Pierre’s Booker Prize-winning debut novel, “Vernon God Little.” The story about a high-school shooting’s been compared to “Catcher in the Rye” and “Huckleberry Finn.”