If you’re staying in Paris, by far, your best bet for getting around the city and its near suburbs is the métro and RER (express métro). Fast, clean, easy to use, and well-priced (€2.50 a ride, as of this writing), it takes you no more than a 10-minute walk—and often much closer—to all of Paris’s principal sights. Cycling has exploded in the capital, and Parisians and visitors alike are taking advantage of dozens of newly opened cycling lanes and bike-sharing (Vélib in Paris). If you’re a pedestrian, be sure to look for speeding bikes before crossing!
You can travel directly to and from Paris to its major airports, Charles de Gaul (CDG) and Orly, on the RER B and certain dedicated buses around town. Paris does not have a set airport taxi fare like some US cities, so Uber or Bolt are almost always cheaper than a taxi. Be aware, however, that locating your ride at the airport can be maddening, as they’re restricted to specific spots that change frequently. Taxis are always available at dedicated stands.
For getting around France, the TGV (high-speed train) is a fast, easy, clean, timely, and economical way to travel between major metropolitan areas. You can research and book your tickets easily on the SNCF website in English. The farther in advance you book, the lower the rates will be. Regional trains are frequent and reasonable but take a little longer, stop more frequently, and you may have to change trains depending on where you’re traveling. A rental car is highly recommended if you’re traveling between small villages.