We've just moved away from Paris to Singapore - I loved it there!
Airports depends on how much you want to pay for ticket and where you are flying from. Orly is cheaper to fly into the Charles de Galle and most of the city hopper flights you will be able to go to Orly. Transport to city from Orly is via OrlyVal (part of
Metro) and will take a little longer than Charles de Galle but is easier.
Shopping is great in Paris - champs élysées is all the high end designer, but there are other great shopping centres like So Ouest for clothes, Le Marie for quirky type shops and the banks of the Seine for flea markets / antiques.
Sight seeing depends on who you are going with and when
the obvious ones are
Arc de triomphe
Tour Eiffel ( book in advance online, google
Visit Paris Tour Eiffel)
Versailles
Sacre Couer
Trocedero
Le louvre
If you like Monet pictures Le Orangerie in the gardens of the Louvre is a real gem, along with the Louvre gardens
Le Grande et Petite Palais
Seine river boat trip
Musee D'Orsay
Saint Germain En Laye ( end of RER line A) huge gardens with view across the WHOLE of Paris
Euro Disney
Parc Asterix
Most tourist attractions/restaurants/shops are closed on Monday, even in Central Paris so avoid Mondays. Taxis are awful so try and stick to the Metro/ RER
Let me know if you want any more info - enjoy!!