Using the métro as Paris transport - I see that Wayne, the original poster, asked his last question in early October, but these more recent posts could be helpful for other Paris travelers to manage métro transportation in the city.
In late September I used a Navigo Easy card/pass loaded with a carnet of 10 trips. (cheaper than purchasing single trips) I also used it on the RER, which is allowed within the central zones of the city at no extra cost.
There were schedules clearly posted in the stations and métro cars of upcoming line closures throughout September and October. Periodic line closures allow for needed work to be completed. We knew to plan in advance to use alternate, available lines and connections. For us it was necessary only once, on a beautiful, warm, sunny Sunday, to walk about 5 extra blocks to use an alternate line.
At one station my navigo pass would not open the pass gate. At some gates you must push it, or a turnstile, to pass through. The ticket window was nearby. The agent said that the gate I had tried to pass was not working. She took my pass to "re-load" one trip and then told me specifically which gate to pass through. It worked. Fortunately I was at a station with a sympathetic agent available and willing to help me.
I would not recommend attempting to use the métro with more than one small roll-aboard per person. Some stations have a lot of stairs. Depending on the day of the week and time of day, the cars may be packed full, leaving some to wait on the platform for the next train.
I used my iPhone with Apple contactless Master Card to purchase the Navigo Easy. However, an iPhone cannot be loaded with trips and used to enter the métro system. You can re-load more trips to your Navigo Easy at a self-service machine using an iPhone contactless Apple Card.
I read recently that there was a day when all contactless payments in Paris were not working... museums, stores, cafés, and ticket booths. Always advisable to have a back-up physical credit card.