CDG is 23 kilometres north east of Paris.
To go from CDG to the meeting place and to the hotels downtown Paris you can either take the AIR FRANCE shuttle
to CDG/Etoile or Gare de Lyon (one way: 16 €/round trip: 27 € tickets to be bought on buses),
RoissyBus to Opera (one way: 9.10 €) or take the RER (train, one way: 8.50 €).
A taxi from the airport to Paris costs about 55 to 70 €.
Orly Airport is 14 kilometres south of Paris
You can either take the OrlyVal to Antony and then the RER to Paris (one way: 9.85 €), OrlyBus to Denfert-Rochereau (one way: 6.40 €
or take the AIR FRANCE shuttle to Montparnasse or Invalides (one way: 11.50 €/round trip: 18.50 €; tickets to be bought on buses). A taxi from the airport to Paris costs about 40 to 55 euros.
The fastest way to circulate in Paris is to use the subway (métro).
The Paris subway is very easy to use and, given the traffic congestion in Paris, is often much faster than taking a taxi or a bus. The various lines are numbered and color-coded. You need to identify the number of the line and name of the station at the end of the line in the direction you wish to go so that you know which way to go in the station.
If you are going to be in Paris more than a few days, or are going to be travelling around the city for sightseeing, it is much cheaper to buy a “carnet” , which is a bunch of 10 tickets for 11.40 €, than to buy single tickets every time you use the subway. The tickets can also be used on buses.
You might also find convenient the visit pass Paris Visite which includes a number of advantages and discounts.