Icelandair has a low $508 round trip fare from New York JFK to Paris CDG for several departure dates in September and October. Norwegian is lower on some dates, but you have to consider seat assignment and checked bag fees and those will make the final Norwegian ticket price higher than Icelandair. From November to March 2017 LOT Polish, Star Alliance airline, will fly you JFK to Paris for $590 round trip via Warsaw.
Icelandair New York JFK – Reykjavik, Iceland – Paris CDG
$508.16 Monday Sep 5 – Friday Sep 16
This same route was priced at $499 on Icelandair last December for travel in January. September should still be snow free season in late summer.
Iceland Free Stopovers
Icelandair allows you to book free stopovers into your itinerary when booking through Icelandair website.
Using these same Sep 5-16 dates where I found low fare on Google Flights, I added a four night stopover in Iceland. The only readon I show Priceline screenshots is the display is easier to read than Icelandair’s ticket price and itinerary.
New York JFK – Reykjavik, Iceland Monday Sep 5
Reykjavik KEF – Paris CDG Saturday Sep 10
Paris CDG – New York JFK Friday Sep 16
$542 is higher than $508 so stopover prices at additional $34. I do not know if fare difference is result of date for topover or additional taxes, but till a small price to pay for a stopover in Iceland. These flights book in economy U class. You can earn 50% flight miles with FinnAir for Icelandair U class.
September is still summer season with fewer crowds for Paris and Iceland.