Originally Posted by
Enthilza
For the Metro, the RATP app is pretty nice (map itself works offline but the schedule and trip planner require data connection).
I have an app that's just called Metro that works offline including the trip planner. I think it costs a couple bucks on the app store. The one thing it needs online access for is real-time news about each line, which can be super valuable when there are service problems.
Personally I just use the Google Maps app. It has improved a lot. I'm always online in Paris though.