I thought the Navigo monthly pass was for locals only, and that tourists have to by the Paris Navigo Decouverte pass. Can you confirm? Thanks.
You can buy & load a Navigo Monthly fare onto a Navigo Découverte card.
The RATP (Paris transport administration) uses this wording on their website:
What card is used to load the Navigo monthly and weekly travel pass?
Navigo monthly and weekly travel passes can be loaded on a personalised Navigo card or a Découverte Navigo card.