The thing about AF TATL is that, while La Premiere onboard is great, I'm not sure it is appreciably more so than BA First. But the best F lounges are in CDG and LHR. So you only get the full experience on the flight west. Though the BA mini-Concorde Room at IAD is nice. For AF, first has a separate room off the main lounge at IAD (sort of like LH has, but more private). Neither is over-the-top like in CDG or LHR (which are only for departures, not arrivals).

By the way, when I fly AF Affaires TATL, I often get a buy-up offer email or at check-in to first for about $1K.