A screenshot of a video about the hair-pulling incident that was uploaded to the Internet.

A viral video that is described to be showing four men dragging a woman by her hair on a street in Shanghai has been misinterpreted, police said on Tuesday.

What actually happened was a man having a brawl with his girlfriend, they revealed.

Police in suburban Baoshan District said they received a public tip at 10:15pm on Monday about a woman being beaten up near the intersection of Gonghexin Road and Gongjiang Road.

An investigation showed that a 30-year-old man surnamed Xu had a physical fight with his girlfriend, a 29-year-old woman surnamed Chen, outside his restaurant, while some of Xu's friends tried to stop him when he was assaulting Chen.

Before the fight, the couple had been dining and drinking with some friends inside the restaurant, but Chen left on her own after having a verbal spat with Xu, police informed.

Chen suffered some soft tissue injuries to her face and knees in the brawl.

Xu was given an administrative detention for assaulting Chen.