Police say the incident happened Sept. 14 at about 1:55 p.m. ET, when a woman driving a vehicle accidentally cut off another driver.
The suspect who had been cut off then followed the victim to a Bank of Montreal drive-thru at 99 Boulevard de l'Hôpital, got out of her vehicle and walked up to the victim's vehicle.
The suspect then grabbed the victim's hair and slammed her head against the steering wheel, police say.
Police put out a call for help on Tuesday and released a description of the suspect, her car and the people who were in the car with her.
On Wednesday they said thanks to tips from the public a Gatineau woman was arrested and charged with assault.
She was released with a promise to appear in court on Jan. 21, 2015.