I was hoping to get some advice on the Navigo pass. I am going to be in Paris in July, arriving on a Monday and leaving on a Saturday night and plan to use the metro/buses a lot. The Navigo pass seems to make sense, given the days of the week I'll be there. I've bought a carnet on past visits to Paris, but I think this pass would be more cost-effective for me this time around. I've had a hard time finding information about it in English on the RATP website, though. My French is OK, but I would be more comfortable reading more in English or getting some practical advice from FTers.

Where can I purchase a Navigo pass? Is there anyplace at CDG I can get one? I'm taking the Air France bus in from CDG and transferring to metro at Gare de Lyon, but thought it might be easier to just get the pass before I got to the metro station. I believe I need a photo for it -- is this correct? \

Any advice/help would be appreciated.