That's a catchy tune, no? El Señor Rossi was an Italian animated series of films that ran from the early 60s to the mid-70s created by Bruno Bozetto. Although as an animator Bruno Bozetto for his film Allegro non troppo which was a humorous take on the Disney classic Fantasia. These days he's been doing quite a bit of Flash based animation.
Found via thisspartanlife.com.