In September I will be in Paris only for a Saturday night after landing at 6:00 pm at CDG from CFE. I want to go into Paris with a client for dinner and some quick sightseeing. Any suggestions? We will want to take the train from CDG and back the Sheraton CDG at the end of the night. Thank you in advance for suggestions.
I would suggest to have dinner at La Maison blanche, with a nice view over Paris and very good menu (not cheap). Another (cheaper) option would Les Ombres at the top of Musée du Quai Branly (more casual/less business oriented).
And if you want to have a short tour, the best thing would be to ask the cab to drive you from CDG along the Seine to see Notre Dame, the Conciergerie, the Louvre Museum, the Institut, the Musée d'Orsay, the Invalides, the Grand Palais, and the Eiffel tower (most major monuments are along the Seine). To do so, speaking French would a plus to make sure the taxi driver understands what you wish.
If there are two of you may I suggest you take a taxi into Paris; it is a little more expensive but less hectic and you dont spend so much time underground. You can ask the taxi to take you around champs elysee, make a quick stop at the Trocadero (as mentioned above), drive through ile de la cite (Notre Dame) and then drop you off in St. Germain area; there are tons of restaurants and places to eat. I can recommend a couple if you like.
Once done, take a taxi back to CDG.