Paris Museum Pass
Here's a link to the Paris Museum Pass. It costs less than the Paris Pass. The difference between the two is that the Paris Museum Pass mainly gets you access to museums and the Paris Pass includes additional things like tours and transportation for the city of Paris and some surrounding areas. I have used the Paris Museum Pass and recommend it because I'm mainly there to see art and culture in museums. The bus tour, wine tasting and river cruise are things I tend to incorporate into my time in Paris without wanting to feel bound by those opportunities. We usually supplement our Paris Museum Pass with a Bateaux Bus pass for a few days which gives unlimited access to the boat taxi that goes up and down the River Seine all day. It's a nice way to see the city from the river in different light, at many times of the day, and get around above ground. If you're not sure which one to get you can read about both of them and make an assessment.
Why wouldn't you want to go to France? History, art, food, wine, what else is there?