Two calendars seen in the background indicate the month is January when Mike and Esmeralda go to Austria, but the newspaper article about the burglary is dated in December.
When the officer who has just dropped off Hudson's lady friend arrives, his patrol car has "23rd Precinct" painted on the side. Yet when patrolman himself exits car, his collar brass clearly says "12th Pct."
When the black and white 8mm home movie that Hudson and Cardinale watch runs out - the end leader that is shown projected is professional lab panel leader that would only turn up on a 16mm print - not on a home 8mm format original film.