The British runway veteran was arriving at Club Haussmann with Gaga when she appeared to become agitated by the huge throng of snappers clamouring around them and suddenly turned on one photographer.
In pictures taken of the incident, Moss, 41, can be seen grabbing the paparazzo's arm in anger before members of Gaga's entourage and security team step in to separate the pair as the singer looks on in shock.
The stars, who were in the city for Paris Fashion Week, headed into the venue after the tussle and cops later arrived on the scene to ensure no one had been injured.
Moss has reason to be weary of the paparazzi - in 2010, she and her daughter Lila were attacked by overeager snappers as they tried to exit Los Angeles International Airport. The incident helped to spur a new public safety law aimed at reigning in the celebrity photographers.