Some days it seems as if the to-do swirling around Martin Scorsese's "The Last Temptation of Christ" will never go away. Tuesday was a case in point, as Paris police arrested 30 alleged right-wing extremists for questioning regarding an act of arson that destroyed a Paris cinema showing the film and injured 13 people. The arrests were made after hundreds of demonstrators had gathered Monday night outside the burned-out cinema to protest the fire and the arsonist. French film personalities and leaders of the Socialist and Communist parties joined the protest in the Latin Quarter, chanting slogans including "freedom of expression" and "fascism will not pass." Even notorious right-wing extremist Jean-Marie Le Pen was at the protest, shouting that the Socialist government of President Francois Mitterrand must share the blame for the fire. . . . Meanwhile, down in South Africa, government censors Tuesday banned "Last Temptation" from the nation's theaters. South African Director of Publications Braam Coetzee said a censorship committee had watched the film and rejected it. He refused to disclose reasons for the decision, adding that an appeal was possible. . . . And back in the United States, an unemployed man drove a bus into a deserted Ithaca, N.Y., theater that is playing the film, then asked police to arrest him when they arrived. The theater was empty Tuesday afternoon and no one was injured, police said, adding that damage to the theater was extensive. The man, Stanley Watin, was later arraigned on a charge of second-degree criminal mischief.