thanks a bunch, guys, for the great answers.
bavaria, you said to a 5 zone ticket as it was cheaper than the paris visite. do they sell multi day 5 zone tickets? we'll be there for 5 days and anticipate going into paris multiple times
THE ONE day mobilis card, is that good for round trip if in the same day or would that require 2. is there any one way tickets? my daughter may need to take the train just back to paris to get her train to nantes one day where she is going to school.
My daughter will only be making the trip back into Paris to CDG airport to say goodbye to her boyfriend and then she has her ticket from Paris to Nantes.