Fodor's recently released "10 Things You Need to Know Before You Go to Paris". It is a good article. Here is a link to it and a few additional notes from us!
1. Dining - You do not need to tip in a Paris restaurant. Enjoy the freedom of not tipping! It is wonderful once you get used to it. Also, remember this phrase "une carafe d’eau, s'il vous plait". Say that and you'll be getting a carafe of water for free instead of an expensive bottle of Perrier.
2. Getting along with the French - If you speak no French at all, download the Duolingo app (it's free) and learn the "Greetings" lesson in full. A little French does go a long way in Paris. Besides, it is an incredibly beautiful language.
3. Arrondissements are simply the name for the different districts of Paris. Nothing to add here really.
4. Paris does close early - but really only when you compare it to New York. Plenty of options later into the night. Paris night life is wonderful enjoy it!
5. The Metro - is awesome! Use it all the time! Watch for pickpockets though - just like in any big city.
6. Accept this fact: when you go to Paris the major monuments will have long long lines. Make sure to find off the beaten path places and neighborhoods. Just start walk in any direction from the Eiffel Tower or the Louvre and you'll find something interesting. Also, take a day trip from Paris with us! Visit Normandy, Mont St. Michel, the Loire Valley and much more.
7. Dress in Paris - I take issue with this one. Fodor's says to "Make an effort to dress a little like a Parisian". I disagree. Be yourself. Do throw a blazer for men and a dress for woman into your suitcase though. You might need it.
8. Paris is a fast city, but Fodor's encourages you to slow down when you are there. I agree. It is your vacation. Take it all in.
9. Paris is a safe city. Pickpockets do a great job so be careful. Also, ignore beggars. Yes, it sucks to see someone in need of food, but an aggressive beggar could be the decoy for someone else to grab your wallet. It happens a lot. If you ignore them they will move on.
10. Saving money - Fodor's has some good ideas, but one I like is to buy some food during a trip to Paris at a grocery store. There are many in Paris and the food is priced reasonably. Also, some restaurants (especially in hotels) are way overpriced. Not worth it.