Police say a man with a gun broke up a fight in a bathroom Sunday night at Bottled Blonde, 504 N. Wells St. View Full Caption Submitted photo

RIVER NORTH — A bathroom brawl Sunday night at a busy River North bar ended quickly when a bystander pulled a gun, police said.

No charges were filed after police responded to the scene at 10:13 p.m. Sunday at Bottled Blonde, 504 N. Wells St. Police said the victim, a 29-year-old man, was punched in the face in a bathroom but refused to sign a complaint against his attacker afterward.

The fight, police said, was broken up by someone "who was legally in possession of a firearm."

The scene still brought out about 10 police cars who shut down the corner of Wells Street and Grand Avenue for about an hour Sunday night, neighbors say. The fight was the latest incident at Bottled Blonde, a popular bar that's drawn the ire of some neighbors for late-night rowdiness since it opened last year.

The bar, a pizzeria that's open till 2 a.m. on Sundays, was subject to disciplinary hearings at City Hall earlier this year.

RELATED: Will Bottled Blonde Be 'Rowdy Hooters,' as Neighbors Fear? Landlord Says No

A recent Lyft study shows Bottled Blonde is the fifth most popular restaurant destination in the city. Bottled Blonde representatives did not return a message seeking comment.

For more neighborhood news, listen to DNAinfo Radio here.