That's an exaggeration. I'm Belgian and recently went to France and took pictures of us enjoying our dishes. I didn't notice the personnel having an issue with that. So it is not a general rule.

But the spirit of bambax' and others' messages is true: in Europe, customer is not king and should behave in a way that pleases the shopkeepers or restaurant owners. This is more true the closer you are to the capital or the city's hot spot.

And more generally, one has to develop a sense of what is right in a particular place, not assuming that the same customs apply as in your home country. Americans don't have a good record at that, I'm afraid. As someone pointed out, you're bound to inadvertently offend people, but rushing into a place with a camera is a good way to start learning from your mistakes.

That being said, the violence displayed by this particular personnel is completely over the top and should not be tolerated, not by customers and not by law.

Depends, as always, on where you go; we avoid Paris like the plague (for assorted reasons, rudeness of owners is one of them), but in villages and small cities (south of france, belgium, netherlands, germany) I feel very much like a king. Especially if you speak the language.