The incident allegedly occurred outside Casa Escobar last Friday in a Malibu mall about 6:15 PM. We're told Brosnan allegedly committed a battery on Robert Rosen, a photographer.
According to Rosen, Pierce was there with his kids, when Rosen began snapping photos (see below). Rosen says Pierce then said, "Why don't you get a real f**king job." Rosen says he then started complimenting Pierce on his Bond roles.
A short time later, an enraged Pierce allegedly told the photog, "Why don't you f**k off, mate," and then struck him in the ribs. A witness says the pap instinctively reacted by kicking Pierce -- we're told, in the stomach.
Sheriff's spokesperson Steve Whitmore says his department is "actively investigating" the matter and will be referring the case to the L.A. County D.A. for review.
Brosnan's rep was not immediately available for comment.