77W is unlikely on ORD-CDG, although anything is possible. CDG is not as "premium" a market as LHR for competitive reasons, nor is CDG a OW hub. CDG also is also more of a leisure than a business market (esp in summer), so likely to be fewer paying full fare for F or J.

I would bet 772 (to be reconfigured with 2 classes of service) if the cAArgo can sustain it, or if not, 763 service.