I'm stunned. You posted this over five hours ago and no responses yet. I won't even begin to list musts in Paris. It would take weeks to visit them all. Many guide books have itineraries that will tell you what to see if you have two days, three days, etc. You may want to go to a bookstore and thumb thru some to see.

In Amsterdam, three absolute musts are the Anne Frank House, the Rijksmuseum and the Van Gogh Museum.