Our travel agent booked 6 tickets for us and 2 other couples on a Delta flight from Chicago to Paris recently. We paid an extra $500 each to fly first class round trip. She said it is flukey sometimes, but we got first class seats for that extra cost. Air France flew the flight and we were seated in Premium Economy. The flight attendant explained that Air France doesn't have first class seating but a business class. Needless to say we were extremely disappointed. The premium economy must be equivalent to Delta Comfort. Our travel agent is upset with Air France. Should we be upset with Delta, Air France or our travel agent? Do we have any recourse?