God, from my experience, I feel like there is no way to go wrong. If you're going to love the city, you're going to love it no matter what you do. And for everything you miss, you'll just tell yourself "next time" because there's no way to not return to Paris once you fall in love with it.
But be prepared for lines! hahaha. Try to buy tickets ahead of time as much as possible for any touristy thing you're going to do.
But be prepared for lines! hahaha. Try to buy tickets ahead of time as much as possible for any touristy thing you're going to do.