You didn't ask, but I'd advise against trying to get into Paris and do any real sightseeing on a six-hour layover. If you and your carry-on take only half an hour from deplaning through passport control, and you return to the airport three hours before your next international flight, that leaves two and a half hours. Getting into and out of central Paris will likely take at least an hour, leaving you maybe an hour and a half in the city. Not enough time to do much, and constant worrying about the schedule. Six hours is a long time in an airport but I still wouldn't chance it.