Have a 12-hour layover in CDG coming up (arrive 11am from the U.S., depart 11pm to South Africa), and am planning on exploring the city. Bags will be checked straight through, I will have no carry-ons, and my boarding passes will already be in hand. How far in advance of the second flight would you recommend getting back to the airport, especially at this late hour? I was thinking 2 hours should be more than enough to get through security and to my gate.