When François and Louise sit in Bruno's taxi, during a cut showing the passengers the taxi is moving, but in the cuts before and after (showing the driver) the same cars can be seen parked on the side as if the taxi was standing still in between.
The goof item below may give away important plot points.
When Bruno calls Francois to help with one question on Who Wants To Be a Millionaire, Francois is sitting at home watching the show. All shows are recorded (i.e. not broadcast live) to ensure that Phone-A-Friends can't simply research questions on the Internet.