I'll be arriving in Paris at 8:10 am via CDG on a Monday and want to take the Paris grand tour (Paris L'Open Hop-On-Hop-Off Tour). What would be the easiest stop to join at? Outbound flight leaves at 6:30 PM. I'm assuming I'd have to head back to airport at about 2:30. Does that sound right?
Take the Air France bus (line 2) to Porte Malliot. It takes about 50 mins and cost 14 euros. Enter the building across the road to reach the Porte Malliot metro station underground. Take Line 1 in the direction of Chateau de Vinecennes. Get down at Concorde. Come out of the metro and wait at the bus stop with yellow hop-on hop-off boards.