Flywatch have amended their plans for serving Paris from SEN.
They are now offering SEN-LTQ-SEN daily except Tuesday and Thursday from March 2008 with a rail connection to Gare du Nord, Paris via Etaples railway station.
The idea of operating into Pontoise (POX) has apparently been dropped in favour of the Rail/Air connection to Paris.
Reminds me of the old Silver Arrow days.