The angry star allegedly lost her temper with the snapper when approached for a picture and is said to have shouted obscenities at the photographer before reportedly lunging at his camera.
The photographer tells X17online.com, "Demi was crazy; she was totally losing it. I was just standing on the sidewalk, trying to get a few shots of her and she was going completely mad. She tried to jump on me and swipe my camera."
A skinny Moore has been showing signs of stress in recent weeks following reports her marriage to Ashton Kutcher is falling apart. The couple has been dogged by rumours of a split ever since the stars spent their sixth wedding anniversary apart on 24 September (11).
Neither actor has spoken out about the allegations or addressed speculation about Kutcher's infidelity, but they appear to be trying to work through any problems and Moore was recently spotted visiting the funnyman on the set of his TV show Two and a Half Men.