transfer from airport

If you are traveling light and know how to be pickpocket proof then it is 10 Euro by train to anywhere in Paris. If there are several of you, it is only 50 Euro for up to 4 and luggage by cab to your location.

The RER B train will take you to Les Halles, which is the center of the city in about 40 minutes. Cost is 10 EUR and the trains go every 7 1/2 minutes. But "best way" means different things to different people. If you have a ton of luggage, maybe "best way" is a 50 EUR taxi ride.

Even if you don't have ton of luggage, a taxi might be the best way. Will you be jet lagged? Are you familiar with using mass transit? If you are not, do you want your first attempt to be after an overnight flight? Even if you took the RER to Chatelet-Les-Halles you would still have to make your way to wherever it is that you are going unless you happen to be staying near that station. That would mean a transfer to the metro or a bus or walking. The center of the city (Kilometre 0) is located in front of Notre Dame. To get there, you would continue on one stop past Chatelet-Les-Halles and exit the RER at Saint-Michel-Notre-Dame station.

A friendly reminder. If you choose to take a taxi, make sure you get it from the official taxi stand. There are signs throughout the Terminals above providing the direction to the Taxi's. Do not accept a "Taxi" ride from someone who walks up to you.

Enjoy your trip.

You did not say which airport...but if you are a solo traveler and want to save money on taking a taxi....there are buses that drop you at a central point in Paris...like Arch de Triomphe or Gard du Nord for instance...this may be a less of a jolt and less confusing way to arrive, you can map your route and take a short, less expensive taxi ride from the bus drop off to your hotel....just check the airport ( Orly? CDG?) website for the bus options vs. trains etc

I always stay in the 7th Arr. so I take the bus to Arch de Triomphe