We have a trip coming up in March. We are flying from Seattle to Istanbul, but we get to enjoy an 11 hour layover in Paris. The timing works out well for us providing the opportunity for a Paris stopover; we should be able to head in to the city center around noon-1:00 pm, and our onward fright from CGD to Istanbul doesn't depart until 10:40 pm. I figure we should have a solid 5 hours of so in the city, but want to be sure I get back to the airport at an appropriate time so that we catch our onward flight with no stress.
For international departures from the USA, I usually aim to get to the airport 3 hours before flight departure time. In this case, we will already have bags checked through to Istanbul, we probably will have boarding passes (though probably not with the current departure gate info), and we will technically already be checked-in for the continuation of our flight (although I plan to "re-check-in"). We will probably need to pick up a carry-on bag that we plan to leave at a left-luggage facility, and of course we will need to clear security. We're flying in business class on Air France, so we should have access to a decent departure lounge (champagne, maybe a massage...). We will probably have lunch and dinner in Paris so we won't be looking to load up on food in the departure lounge.
Given our task list, how many hours before departure time would be appropriate to arrive back at the airport after our afternoon/early evening in Paris? I plan on taking the RER B both ways. It will be on a Tuesday evening in March.
Thanks!