It appears your travel agent was correct in that Air France no longer codeshares with Delta on the Athens to JFK non-stop. Since the flight was booked as an AF flight and the AF flight number was canceled by AF, it would have been handled like any other schedule change. Since AF doesn't have non-stop service from ATH to JFK and there was no space on the DL flight to rebook you then connecting in Paris was, unfortunately, your only option.
I'm not sure why Delta was so forthcoming with compensation since AF was responsible for re-booking you, however since you were on a European carrier on a flight which originated in an EU nation there may be some compensation due to you if your arrival in JFK was delayed from it's original time on the non-stop. If your arrival time was 4 hours later or less you should be paid 300 Euro (about $445 USD) and if you arrived at JFK more than 4 hours later than originally scheduled you should receive 600 Euro (about $890 USD).
Connecting flights aren't always less expensive than non-stop flights so you really don't have a claim there but you do under the EU rules since the AF flight was cancelled (due to the change of codeshare agreement) and your arrival at JFK was delayed.
|