Vigin Atlantic with codeshare partner British Airways, via Priceline, have roundtrip airfares travelling from Los Angeles (LAX) to Nice France (NCE) for $564 including taxes and fees. This makes 1 stop in London.
Travel Availability.
Departs LAX: every Sun/Mon/Tue/Wed beginning Oct 31 thru Dec 6
Returns LAX: every Sun/Mon/Tue/Wed/Thurs beginning Nov 7 thru Dec 13
Use dates above and book it on Priceline .
Sample travel itinerary attached.