The biggest fun we had on the Paris Metro was on the RER double decker trains. Unfortunately for us we only got to go on the one.
We'd never used the Metro before (other than DH for a couple of stops when at the Paris office for work) and at first it was mind boggling. How the heck did people know where to go to. We found our way out to street level and visited Notre Dame. Then we had to get back on the Metro to go to the Eiffel Tower. Choosing a different station was a good idea as there weren't so many different ways to choose from to go. However it took us a while (and letting a couple of trains go by) to work out how to get the train we needed. With that sorted it was a breeze and Paris became so easy to get round for us. .
Paper from Paperhouse Productions - Paris Map. Die cut Metro embellishment and tickets originals (minus the one for DH which he managed to lose somehow on our return to DLP !)