Delta Airlines has low fare tickets from New York JFK to Paris CDG for $547.40 round trip with dates from September through March 2016. This fare has been around for two days now and looks like it might end soon as some of the Google Flights fares price a couple hundred dollars more when clicked through to Delta website.
I was able to find several dates with availability. The low fare appears to be found looking for Delta codeshare nonstop flights flying Air France.
Delta Airlines codeshare ticket for nonstop Air France flights.
New York JFK – Paris CDG Tuesday September 22 – Tuesday September 29
$547.40 Flight Miles: 7,269 miles in economy V class. $433.60 base fare for MQM and SkyMiles earning credit.
Delta Airlines New York JFK – Paris CDG (Delta operated nonstops)
$547.40 Tuesday March 8 – Tuesday March 15
Thanks to @FlightFishing on Twitter for this fare alert.