Ground services at IAD exist but are (compared to CDG) underwhelming. Separate check-in counter, and they'll walk you through security, onto the train, and then into a private room within the Air France lounge. They'll then escort you onto the plane -- your choice of boarding first or last. Upon your return they'll have someone waiting for you at the gate, but you'll still have to take the people-movers and go through all the normal lines.