A password will be e-mailed to you
Take always small change with you! If you will need a public bathroom, you will probably pay 0.50 € to enter.
Remember that floor numbers aren't the same of U.S. ones. In Europe we have ground floor / floor 0. It is the corresponding of the 1st floor in U.S.!
French people are nationalists: try to speak few French words. You will make them very happy!
Check the weather forecast in advance so you will know what to put in your luggage!
Even if they say it will be sunny all the time, take your umbrella with you anyway.
Read my article about transports pass to know which one is the best for you!
If you want to buy something very luxurious, go to Lafayette Galleries.
Don't be worried about the need for a car in Paris. Taxis and Uber are a lot!
For your safety, provide you a travel insurance
Study everything about transports in Paris reading the transports page of this site