Eighteen people were arrested, including two minors, following a riot in a normally tranquil suburb of Montreal.
More than 200 people, who were at a Blainville, Que. outdoor concert by the alternative rock group "Les Trois accords," refused to leave the park after the show ended around midnight.
Police say they threw bottles and other objects at officers and set a squad car on fire.
Local cops needed help from other forces, including Quebec provincial police, to regain control.
The riot was quelled in the overnight hours early Sunday morning.
Charges will include mischief, participating in a riot, and arson.
All eighteen were released on a promise to appear in court at a later date.