All alliances have New York JFK and Newark EWR to Paris CDG/ORY on sale for around $450 round trip from January to May 2018. This ticket price is discounted to $387 on some dates with AARP British Airways discount link for January to March departures.
American Airlines maintains $450 fares into May, but BA-AARP ticket prices I see are in the $436 range for May 2018 departures due to higher $500 ticket prices with British Airways.
Many of the lowest British Airways AARP ticket prices are flights on Open Skies, American Airlines and Aer Lingus.
British Airways AARP discount ticket
New York JFK – Paris CDG / Paris Orly ORY – New York JFK