Gratuity guide

Nada. It is not expected. That is an American custom not a French one. But give whatever you feel hopefully not awkwardly. It is not about being able to afford to tip. Sometimes it easier to round so you are not expecting change

We always tip about 3-5 Euro for a cab or driver, 1Euro each for a bus where the driver puts the bags under the bus. Same in the US but in dollars. The idea that it's not a tipping culture in France isn't true. Movie theater ushers were tipped 50 centimes back in the day--but even in an empty theater with your choice of seats. It's only waiters where the culture is different. Having family friends who spent their lives driving Paris cabs, we've never think of not tipping. If I can afford a plane ticket, I can afford to tip. True that it's not compulsory or it would automatically be added to the bill.

Zero, Zilch, nowt. Tips are never compulsary.

If you are talking about Charles de Gaulle airport, there is a fixed taxi fare between there and Paris city. Either €50 or €55 for the right and left bank halves of Paris respectively.
Train (RER) cost €10.30 per person to any métro station in Paris, and may be quicker, but you have to carry your own luggage. Details here: http://easycdg.com/rer-charles-de-gaulle-airport-cdg-to-paris-by-train/

Thank you!

Americans really feel compelled to tip - Europeans may leave an extra euro or two...maybe. Don't feel compelled.

Tim, so true! Thanks!

One way to guarantee a grasping tipping culture for Americans but no one else, is for American tourists to push money on waiters cab drivers etc. It is not a French custom but you will see waiters in touristy area blatantly asking for tips from American tourists. A cab driver is not tipped although if they do some special service it is nice to do. e.g. my cabbie a year and a half ago when my arm was in a cast came into the apartment building and got all my luggage and took it to the cab and then at the airport got me a cart for luggage; I did tip him.