Returned a couple of days ago from our 5 nights in Paris, and will be posting my trip report soon in the next day or so. Thanks to everyone for all the great advice, especially about transportation (loved the carte orange).
Before I post my trip report, I did want to ask about something.... we stayed at the Hotel Sainte Marie (near the Bonne Nouvelle metro), and twice while taking back alleys from our hotel to the Musee des Arts et Metiers, we came across what was obviously a street being used by prostitutes. It was odd for a few reasons--the two streets (they were different ones each time) were areas full of clothing stores, and it was the middle of the day--the stores were open for business, they were just surrounded by prostitutes. Anyone know anything about this? We just thought it was a little odd. Do the stores allow this? Do the cops try to crack down on this?