From the Telegraph
The Louvre is concerned about the increasingly popular gadgets being waved around within inches of the Mona Lisa and other famous paintings that tourists love to use as a backdrop for souvenir shots.
They are not yet banned at the museum, but a spokeswoman said: "Users must follow the rules and not point any objects at paintings, sculptures."
What's the point in going to an art gallery if you can't brag to your friends about it on Twitter? You might as well just go and see a movie.