A jacket! Believe or not, although I visited in the summertime, much of my time there was accompanied by rain.
Deodorant! French people don't love to wear this, so it can be helpful if you remember.
A pair of headphones. You'll do A LOT of walking, and listening to music at the same time can help you feel like the main character.
A decent outfit. French people dress extremely well, so unless you want to obviously look American, spice up your wardrobe with something fancy.
Ice! Just kidding. You can't pack that to last two weeks. You won't be able to find any though, unfortunately.
A bag with a zipper. Many people like to pickpocket in Paris and on the subways, so it can be helpful to have a bag that people can't just reach into and steal from.
A comfortable pair of walking shoes. Trust me, you'll value these.
A French/European outlet adapter. Without this, you'll have trouble charging your phone.
A good book. Make yourself feel aesthetic by reading a cute novel.
Your childhood stuffed animal. Trust me, when you start to get homesick, you'll need a familiar friend.