Paris is served by three international airports – for more information, including arrival/departure times, check the official sites.

Charles de Gaulle International Airport (Roissy)

CDG: This is the major Paris airport of the city. It’s a very confusing airport, so allow enough time for between connections and flights. There are 3 terminals: Terminal 1, Terminal 2 (which is very big and divided into multiple sub terminals), and Terminal 3.  Theres a free shuttle train that connects all of the terminals. Everything at the CDG airport is very expensive, particularly the food. If you’re traveling from Terminal 1 it’s also worth noting that the food court is located before the security check so make sure you eat first. It is very hard to find a bench in which to sit.
There are no public showers at this Paris airport. Air France offers public shower facilities, and the departure lounges have showers. Though lounge access is included only for Air France business and first class travelers. Some members of the Air France frequent flyer programs can gain access depending on their status level. Some lounges may grant access to travelers on their flights for a fee. If you are willing to pay for access to the lounge, inquire at the check in booth when checking in for your departure. If you must have a shower cant manage to gain entry in to a lounge, the airport hotels generally have rooms available and you may ask for a special fee to just use a room for an hour or less. When you arrive at the airport, you should note the terminal in which you arrived at because when you come back, the subway train makes two stops at CDG,  there are few indications of which airlines are at which terminals.

Orly International Airport

ORY.  This old international airport is used by Air France for its domestic departures, and international departures by European carriers. Orly is about 40 minutes away from Paris via the OrlyBus, which departs from Métro Denfert-Rochereau; and costs about €6. Every 10 minutes, you will find buses from the Orly Sud (Platform 4) and they stop at Orly Ouest on their way to the city. Tickets can be bought at a counter near the baggage claim area and directly at the counter in the fourth Platform. The tickets need to be validated when you board the bus. Yet Another option is to use bus 285 that takes you to the Métro Villejuif – Louis Aragon in about 15 minutes. This one costs €1.80 and runs every 10 minutes.

Beauvais (Aéroport de Beauvais Tillé)

BVA. This is a smaller regional airport that is used by some low-cost carriers such as Ryanair and WizzAir. Beauvais airport operates a shuttle service that connects with the Metro lines at Porte Maillot station. Buses run most of the day, starting at early hours of the morning (6AM). The Buses leave the airport 20 minutes after each flight arrives, and a few hours before each flight departs. The journey will usually take about an hour depending on the traffic, and it costs €15 each way.