“Django Unchained” star Christoph Waltz and French actor Daniel Auteuil were being interviewed at the Cannes Film Festival when what sounded like gunshots rang out, causing chaos yesterday. The actors were appearing on French TV show “Le Grand Journal” on an open-air set by the beach, then suddenly gunfire sent the audience into panic as the two were rushed offstage by security, video of the incident shows. Police then pursued a man with what looked like a gun, and arrested him, reports said. But the weapons luckily turned out to be fakes. Waltz said in an interview, “A man produced a gun. I think it was a pistol, and he fired, but luckily for me they were blanks. Then he shouted he had a grenade, and again luckily for me there was no grenade . . . The police tackled him to the ground.” Waltz added, “I’m fine, there’s nothing to worry about.” Cops reportedly found a “dummy grenade” and a knife on the suspect. Two-time Oscar winner Waltz is on the Cannes jury this year with Steven Spielberg, Nicole Kidman and Ang Lee.