In Jay Z's defense I saw him in person and didn't know who he was til someone told me it was him LOL.I remember I saw Britney Spears out and about and since I didn't get a good look kept asking who it was.
It happens a lot of times when I see stars out an about in LA. All you see is commotion and them in glimpses.
It was a private tour of the Louvre. Of course you wouldn't see a lot of people and unlike some people, they don't call the paps to alert them of their every move.