Question: using pre-bought RER tickets to "wrong direction"
 

I just booked a spring trip to Paris, so excited! Only three and half months to go :D

I visited Paris this summer with my boyfriend and I had bought us RER tickets for CDG airport - Paris, but when we landed we found out that the regular RER B train had just stopped running and there was instead a bus connection from terminal 3 to Gare Du Nord. We ended up taking a a taxi because we wanted to get to our hotel as fast as possible. So now I have two tickets left that say CDG airport -> Paris, but I checked that the RER B is still being replaced by bus during late evening, so I think we will again rather take a taxi than deal with several shuttle/bus/metro changes.

Is it possible to use the tickets going from Paris to CDG airport or is the direction printed on them more important than the zones they are valid for? :)

It's the zones they're valid for that matters.
I'm a Parisian (ok, I'm from another part of France but I've been living in Paris for quite a while) and I can assure you that you want have any troubles.

When you buy a trip both ways out of Paris, most of the time you're two tickets are marked the same way, Paris --> Versailles for example, and it work in both directions !

Enjoy your trip to Paris, and don't hesitate if you have any other question !

As Tipoule said, the ticket is valid in either direction.

However, to answer your question more precisely, single RER tickets are not priced on zones (unlike weekly or monthly passes) but based on a specific route written on the ticket. You can travel that route in either direction but you cannot use this ticket for just any trip within zone 5.
Véronique

Thank you for your quick answers! :)

Traditionally and for transportation in the past I would agree with the above posters. However, I have heard that some of the RER tickets now sold are indeed direction specific and may no longer be used interchangeably (inbound/outbound) along the same route.

I have no recent experience with this change but if someone does find that an inbound ticket will is not valid outbound within the same two travel points, I should be very interested in hearing the details.

Sarastro, the "Billet Ile de France" which we are talking about has just been renamed "Billet Origine-Destination" but the rule hasn't changed: it can still be used in either direction.
http://www.ratp.fr/fr/ratp/c_21187/b...e-destination/
I live on RER A in the eastern suburb of Paris and use such tickets and haven't heard of any change. I think maybe the new name caused some confusion but that's all I can think of.