During the very first song, when Rhea hands Karan his messenger bag, he fails to hold it and the bag is shown dropping into the water below from the dock on which they are standing. In the next shot, Karan is wearing the bag as earlier.
Before the song "Gore Gore Se Chore" Saif Ali Khan's character asks the girls from the bridal party whether Romeo and Juliette were married and they reply 'no'. While actually, Romeo and Juliette were married.
Flashback scenes set 10, 6, and 3 years in the past show the main characters using modern mobile phones that were unavailable at the time.
Dutch scenery, license plates etc. in Paris scenes (the whole Paris section is actually filmed in Amsterdam).
The woman in the park talks Dutch to her daughter and when Rhea (Rani) speaks to her, the woman starts speaking French (with a Dutch accent!)