Hi Parisbound,
I'm assuming you're looking to travel to
Asnieres-sur-Seine in north-west Paris. If this is correct then the route would be as follows:
- RER B from CDG to Paris
- transfer at Chatelet-les-Halles to Metro Line 14 direction St. Lazare
- transfer at the terminus station (Saint Lazare) to Metro Line 13 direction Asnieres-Gennevilliers Les Courtilles until station Gabriel Peri or Les Agnettes which are in Asnieres-sur-Seine
Total travel time is about 1 hour 10 minutes at a cost of 8,40€. You can use a single
Billet Ile-de-France ticket for the entire journey.
Have a look at the
RATP route planner for more information about this or other routes.
Best regards,
Ben