The prostitute (Elisa Morucci) whom Renato makes love to is not named in the film and in the end credits, the character's name is revealed to be Lupetta.
Nino's position changes when he falls to the ground after he is hit. He is first on his left, then more on his back. His position relative to the steps also appears to change.
The bike that Renato rides, suddenly has a modern derailleur-type chain tensioner at the rear at about 20-21 minutes into the film. At all other times, his bike has a fixed rear gear without the chain tensioner.