“Just start shooting these people.”
I’m not ready to go that far.
However, a rather vicious assault on the person’s hands with a hammer should cure them of any future ideas.
Think of the movie “Casino” - but with more hammer strikes...
I am.
The art that's in the Orsay (and other major museums) was selected because it's a material link to our past. If we allow them to continue this terrorism, even if they don't destroy the art they still will destroy our access to it. In which case we lose a link to our past that has no substitute.
As it is now they get little more than a slap on the wrist, and it makes them a hero among their peeps. The way the officials are dealing with it now WILL NOT stop them. The only way to stop them is to inflict a punishment that's so severe and so certain that they're not willing to bear it.
Kill them where they stand. If they glue themselves to a work of art, ... that's what the Sawzall was made for (but cover the art with a tarp first to protect it from the splatter).