The story is set in Rome, 1921. Ulysse (Alain Delon - this was the 2nd time he worked with René Clément after Plein Soleil. Clément later would use him again in Les félins and Paris brûle-t-il?) and his friend Turiddu, have finished their military service, are looking for jobs. They join the fascist party and are given task to find a printing shop which prints anarchist pamphlets. Ulysse finds the shop, owned by the family Fossati, but falls in love with his daughter Franca (Barbara Lass), and pretends to join their resistance and adopts a name of war Campo Santo (=cemetery), and is about to lead them to bomb the generals who comes to celebrate peace in Rome. However, as usual, when important political guests arrive, the police come to arrest the Fossati family and all their friends. The real terrorists come and they bring real bombs (unlike Ulysse whose bombs are made of cauliflower and melon) to kill the generals, and to clean his name, Ulysse must stop them by gathering the bombs they have scattered in the Fair for Peace.
I read that in this movie René Clément poured in details about fascists vs anarchists, for example: how Fossati names his children, the anarchist flag in the sky of Rome, the fight in the butcher's shop, the man who lives in the attic. The 2 real terrorists are dressed typically. It's funny when the bouquet of flowers they send to the generals returns again to them, still with the bomb. The prison is like a hotel, the prisoners can get out and in as they like.
I love the cute theme-song, too.