We are going to be staying in Poissy in June, traveling to Paris (Notre Dame Cathedral). Do we need to purchase tickets before we arrive in France or can we purchase them the day of travel at the train station.
Is there a senior rate as we are both over 60 years of age?
RER train seats are not reserved so you can purchase RER tickets on the day of travel. Purchasing RER tickets ahead of time gives no benefits in price, availability, nor seating.
Unfortunately there are no discounts for RER tickets for seniors, only children 9 and under.