In 1937, the Nazi party organized one of the most notorious art exhibits of all time. Works by the best and the brightest — Paul Klee, Marc Chagal, Vassily Kandinsky — were hung up, ridiculed and called “degenerate.” Now, a new show at the Picasso Museum in Paris brings some of these works back together, in an exhibition called “Degenerate Art. Modern Art on Trial under the Nazis.” The World’s Sarah Birnbaum reports.