The Alfie star was enjoying a night out at exclusive hotspot Automat when he allegedly clashed with the unnamed woman, who was taking pictures of him leaving the venue.
The 28-year-old photographer alleges that Law hit her on the head and slapped her in the face in an unprovoked attack, which was caught on camera by other members of the paparazzi.
The photographer tells British newspaper the Evening Standard, "He hit me full on the face, it was a real stinger, it was very sore.”
It is not known whether the snapper has reported the incident to the police.
Law has previously landed in trouble over scuffles with the paparazzi -- in 2007 he was arrested on suspicion of causing actual bodily harm after he attempted to grab a photographer's camera. The actor escaped without charge.
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