Metro day pass

I don't know how long you will be in Paris and how many people in your party - but I would recommend buying Carnet (a pack of 10 metro tickets). You buy them at the ticket window in any metro station.
I was with friends and we bought Carnet pks and just used them as needed.
If you have any left over - you can use them on your next trip to Paris.
Hope you have a wonderful trip.

Yes, there's a one day pass, called a Mobilis ticket. It currently costs €7 for validity within Paris; you can get it for more zones for more money, if you're going to Versaille or Disneyland Paris. It is not valid on the RER to the airports, but is valid on buses from the airports that connect to the metro (assuming you buy it for the right zones).

It's hard to find information on it in English, and some of the automated ticket machines don't show it on their English menu, either. Here's a good summary from the Paris By Train site, in English: http://parisbytrain.com/paris-metro/#mobilis

Lots of people will tell you just to get carnets (10 tickets bought as a pack, shareable, for the price of about 8 tickets bought singly), and that certainly works too. But, like you, I'm a fan of the unlimited transit pass like this. However, if you use carnets, you would be able to take 5 trips for the price of the Mobilis. Your call. The tickets from the carnet are not only shareable, but don't expire, so you can simply save unused ones for another trip, or a friend, or give them to others you meet in Paris who are staying after you leave.

EDIT: I see that while I was composing my post, someone did indeed recommend carnets {g}.

Helmut Newcake? Yes, I've tried it, it's absolutely excellent.

Sorry for not adding more details.

There are four of us (teens and parents), so not sure how the carnet would work out.

Remembered this morning we would want to get from CDG to downtown Paris. Planning on staying near Gare de Lyon because leaving for Lyon next day.

Kim, I am definitely heading to that bakery! Three of us have Celiac.

Harold, not heading to Versailles this trip. That's for next year. Basically want to get from airport and move around all day. So the day pass would be a good option?

Thanks for all the responses.

"There are four of us (teens and parents), so not sure how the carnet would work out."

Assuming you are all traveling together, one carnet would give you 2.5 trips, and two carnets would give you five trips. The carnet is just 10 single tickets bought together for a discount; each rider needs his/her own ticket. Two carnets would cost €27.40, and four Mobilis tickets would cost €28.

So, if you're definitely taking fewer than five trips, get carnets; if you're definitely taking 6 or more trips (3 round-trips), get the Mobilis; if you're taking 5 trips, it's a wash. Remember that the funicular up to Montmartre is a separate ticket, and if you take a Metro and then a bus, that's two of the individual tickets from the carnet; in these situations, the Mobilis starts to pay off fast. There's also the luxury of being able to take a short Metro ride without thinking about the cost; if you're just there one day, you're more likely to be zipping around in this way. I like to be able to hop on the Metro anytime, but others prefer walking more.

For getting in from the airport, since there are four of you, a taxi is probably best (not much more expensive than four RER tickets, and more comfortable as well). I have no personal experience, but others have posted that you can get Metro tickets at the airport information desk; just be sure you get the cheaper ones good for Paris only, not the more expensive ones good for more zones.

Ginger,

I am also gluten free. Helmet newcake is good. I came across another great GF cafe called chambelland actually selling GF bread. Give it a try! I wish there were more places like chambelland where I live. It is located off oberkampf close to the st Martin canal which makes a great stop for lunch or snack after visiting the canal. Enjoy!

The carnet is 14.10 for 10 rides. Most people in Paris for a day with 4 people (anyone 10 and older is an adult for riding the metro) would use two carnet. Since the Mobilis is not much more than that, having the MObilis pass might work best. This is a nickel dime decision -- if you misguess on the carnets, you buy another -- nickel dime.

There are no zone 3 or 4 or 5 tickets. Any trips outside central Paris require specific point to point tickets i.e. from Paris to a particular station. Not all stations in a zone cost the same amount to reach and the tickets are no interchangeable.

for the trip from CDG to Paris it is 10 Euro per person so 40 Euro for 4. For that kind of money the convenience of a taxi makes the slightly great cost worth it to most people.

A tip for anyone purchasing a carnet. (Perhaps this is common knowledge but it caught me off guard.) At the ticket machines at the stations (RER, Metro) I was expecting to see an option for 'carnet'. It's actually one of the 'packaging' options under the "t+" (single ticket) choices at the top of the menu of choices. After selecting t+ there is a screen for number of tickets; the carnet (10 tickets) is simply one of the choices there.

Also, we have a 'chip' credit card so didn't expect to have trouble using it to purchase the carnet from the machine -- I had, after all, used it without an issue throughout Nice, including at an SNCF machine. However, the Paris machine wanted a PIN, which I didn't have so I had to use cash (and all coins, at that). Once in our room I contacted our card company and easily got a PIN, with an explanation that unattended sales points in Europe often ask for a pin for credit cards.

A chip and signature card is not much better than a magnetic strip card in France. They use chip and pin. There are some machines that take magnetic strip cards e.g. the Louvre ticket machines, but they are rare.

Carnet means 10 tickets. While in Paris a carnet usually refers to 10 t+ ordinary metro/bus tickets, you can also buy a carnet of any other sort of ticket. e.g. If you were staying at the airport or at Disneyland and commuting into Paris every day (a terrible idea of course) then you could buy 10 of the CDG/Paris or Marne Le Vallee/Paris tickets i.e. a carnet of those tickets at a discount. They would of course cost a lot more than 14.10 -- I would guess for example that a carnet of CDG/Paris tickets would cost about 80 Euro -- but they would be 100 Euro bought separately. If ten of your were making the trip you would save 20 Euro or same if 5 were making the round trip (of course with 5 a taxi would make much more sense.

So 'carnet' cannot be a choice on the ticket machine except under t+ for Paris tickets as there would be carnet options for any type ticket.

PS to OP -- there is no '24 hour' ticket. A Mobilis day pass turns into a pumpkin at midnight and is good from the time the metro starts which is about 5:30 am. Probably could use it on the night bus before that -- but if you buy it on arrival in the morning, it stops working at midnight. (even though the metro runs past midnight)

If you are transferring from one metro to another, or to a bus, or RER on the same trip within a certain amount of time (I think it is 75 minutes from first stamp), you just use the same ticket at each transfer. You don't have to use another ticket. Some of the tickets we had "demagnitized" and wouldn't let us through the ticket stall, but if you take them to the service window, they will give you a new one.