I was skeptical, but this calculator is pretty dead on for a tax trip from CDG to our apartment. They even ask what time you'll be traveling so they can factor in waiting in traffic time.
[From Taxi fare in Paris from Aeroport de Paris Orly France to hote mercure tour eiffel - worldtaximeter ]
Worth a look so you can prepare your Euros and your shocked face ahead of time.
However, the issue isn't whether it's possible as a parlor stunt, but how could you have a fulfilling Paris experience while skipping most of the things around you. It's hard to imagine a once in a lifetime Paris vacation spent entirely outside while trying to avoid museum fees, but there is a free Sunday of the Louvre. ... Best advice if you really want to stick to this budget: get a hotel outside the city on the RER line and zip in in the morning and go back out to sleep.
Delightfully local in Paris On a no-frills budget? Drop the tourist routine and savor the City of Light’s simpler luxuries [From On a budget? Live like a local in Paris - The Boston Globe ]
A Paris Greeter will make sure you discover the true Paris, the way Parisians live it and love it! ... All our volunteers are Paris lovers who like to share the art, tradition and culture of this fascinating city. At the end of the walk, we really want you to have the feeling that you have not only discovered the city but also had an insight into what we call the “Parisian way of life.”