Originally Posted by
Xyzzy
One way tickets don't have to be expensive -- you just have to be willing to choose an airline that offers decent prices on one-way tickets. Try pricing a one-way ticket on TP via LIS. They have one-way tickets between US gateways and Europe for relatively reasonable prices. Another alternative if you're okay with it is to issue a UA award, which allows one-way travel with n

penalty.
^ This. And it's not even relatively cheap, it's downright cheap. And it doesn't have to be via LIS, it can be via OPO too. And a stopover in LIS/OPO is permitted for no extra fare.
We don't know your travel dates and final destination, only that you mention Sep 2017 and CDG. Here is a Sep 2017 JFK-ORY on TP for less than $200 (MR territory).
New York (JFK) to Lisbon (LIS) — Mon, Sep 25
TAP Portugal 208 Dep: 11:25 pm Arr: 11:20 am
Airbus A330 Economy (O)
Layover in LIS
Lisbon (LIS) to Paris (ORY) — Tue, Sep 26
TAP Portugal 432 Dep: 2:35 pm Arr: 6:00 pm
Airbus A320 Economy (O)
Cost per passenger (including taxes & fees)
$199.70