The world's largest underground railway station, the Station Chatelet - Les Halles is located…read moreunderneath the Westfield Forum des Halles shopping center. It's also the most convenient place to take a connection from the Paris Metro line system to the RER airport lines.
Loaded my final trip for 2,5€ on my reloadable metro card on the morning of Day 7, taking line 1 to stop Chatelet. I made a mistake here: knowing I needed to connect to RER Line B, I couldn't find any signs so ended up going outside. Google maps seemed to indicate that, but thinking back, I am realizing that there must have been an underground connection between them. Navigating the outside with luggage in the rain was difficult. But after entering the shopping mall, I just followed the signs for RER. I found a machine to purchase an airport ticket, but it refused to work with my card that I had been using all along on Metro (it had the airport option grayed out...which was frustrating...showing that it was the right machine, but that I was doing something wrong). The only option was a bus to the airport which I definitely did not want. I then began to wander around until I found a staffed office. I tried to explain my situation to the older gentleman..he scanned my ticket, got exasperated (I think with the situation, not me) and told me I needed to go a ticket office to get it fixed. I was going to leave, but then a younger woman intercepted and told me she could fix it. She took my card, did 'something' to it, and then told me I could use the machine now. Sure enough, when I scanned the same card, it now gave me the option to purchase an airport ticket (13€). There is definitely something strange about how you can have the right paper ticket, but if it wasn't initially set-up a certain way, it won't work in all case. Not a good thing for a tourist.
I paid the $15.18 (13€) and used it to scan through the gates (which were for all RER various lines). I then followed the signs for the airport line. I boarded the first train that came, and it ended up being OK. The journey took a while, going through five stops to terminal 2. Most people got off before then. I got off at the last stop, and had to scan my ticket to exit before I could enter the airport. Got to the airport station by 11:33. I had left the hotel around 10:15 so it takes a while...an Uber would have been around $35 for the journey. I'm glad that I experienced it, especially since I was by myself. But I see the use of Uber when in Paris next time.