Originally Posted by
Efrem
Last RER train to Paris leaves T1 at 11:55 pm, T2 at 11:57. Your airline, or other online information sources, can tell you which terminal they use.
I think you mean T2/T3 - RER doesn't serve T1 (well, via a shuttle bus it does, but not directly).
For late night transfers, RER B can be a little sketchy - I used to live near the Luxembourg stop, and it was my perferred way to get back and forth, but there were definitely a few questionable characters late at night.