Louvre museum: Book your tickets online. Queues are usually huge and takes a few hours. This si where the most famous Monalisa is showcased.
I would recommend spending a day here if you love seeing many things that you might have only seen in photos.
Note:The painting of Monalisa is kept in a room, you will see most of the people standing against it and trying to take selfies with out even bothering to
take a good proper look at the actual painting:)