Hi - I would never use a consultant - but that is just me.
Can you leave from someplace other than CDG? There is not a lot of *A there.
I do see seats from CDG to ZRH so that might be an option - though at the moment I don't see any seats out of ZRH.
I see seats available on July 18 from:
LHR to IAD (UA)
LIS to EWR to IAD (TP and UA)
FCO to YYZ to IAD (AC and UA)