I think if you come here, everyone gets the bug.
From books to everything else, I would suggest that you be strategic in your shopping experience
Souvenirs - go to a grocery store. From soap, salt, and chocolate - for people that are a lower priority in terms of shopping - you can get a lot here rather than bits and pieces.
Handbags - Printemp, Longchamp, Louis Vuitton (don't go to 101 Champs d'Elysee - find another one).
Don't buy from street vendor - its not worth being scammed.