In 1940, while living in Geneva, Piccio met his former enemy and long-time friend, Belgian ace Willy Coppens. Coppens mentioned that they must be enemies again. Piccio showed him a cigarette case salvaged from the wreckage of an Austro-Hungarian plane, and remarked, "From 1915 to 1918 Italy was at war to eliminate the spiked helmets and now Mussolini has brought them back to us!" During World War II, Piccio continued to live in neutral Switzerland. He helped Italian soldiers who sought sanctuary after the mid-war armistice. He was also a liaison between the Italian and French resistance movements.