Originally Posted by ranskis

You should rather book, just before going to GIG airport, a flight US to Europe one way on a big carrier (not a low cost like norwegian) on expedia.com (US version of the website) with a departure 10-15 days later than your GIG CDG. Once you arrive in Paris and clear immigration and customs, you connect on expedia.com and cancel your ticket for free. In this case, you should have at least 24 hours free cancellation window after you buy a ticket.

Check the cancellation deadline during the booking (it should be written "free cancellation until ... " next to the fare). And once you get the eticket confirmed, check on your booking for this information, take screenshot just in case you run into issues during the cancellation. I had issues only once and it was quickly resolved by phone, did not even need the screenshot. This way you save the FB cancellation fee.