Toronto police Const. Wendy Drummond says a fight broke out between people in the a downtown Vietnamese restaurant around 3:30 a.m. Saturday.
At least two videos, quickly posted to YouTube and other video websites, show a man hurl a plate into a group of people — some wearing Halloween costumes — hitting a woman square in the face and shattering the plate into pieces.
Drummond said the 26-year-old woman was sent to hospital with non-life-threatening injuries.
"They were to her face and (she) potentially may have further damage," she said.
The fracas appears to have started between two people — with one of the videos showing the victim caught in between them when a man grabs a plate from a bin of dirty dishes and throws it into the melee.
One video of the incident has racked up more than 252,000 views on YouTube since it was uploaded Saturday to the video-sharing website.
Drummond said police are reviewing the videos and will be releasing images of the suspect taken from the footage.
Police say they're looking for a male suspect in his early to mid-20s, around five-foot-nine with short black hair shaved on both sides and a muscular build with multi-coloured tattoos on his left arm.
He was wearing a costume vest with "SWAT" written on it, a tight black t-shirt and black pants.