Il giorno più corto (also known as The Shortest Day) is a 1962 Italian Comedy film directed by Sergio Corbucci. This parody of the war movie The Longest Day stars the popular duo Ciccio Ingrassia and Franco Franchi in the leading roles. Dozens of many other well-known actors accepted to appear in the movie in cameo roles for free, to avert the bankruptcy of the production company Titanus.
Don’t trust the plot described in the English version of the wikipedia page. Indeed, the action doesn’t take place during WW2, but during the Great War.