Mayor Denis Coderre said Wednesday the city will not appeal the acquittals and will withdraw the roughly 2,000 pending charges against protesters.
"For us, it's a question of interpretation, regarding the bylaw and the evidence," Coderre said. "The logical step was to say we're going to drop the other pending cases."
Some protesters were facing multiple charges and therefore Wednesday's decision affects roughly 1,200 people, according to the city's lawyers.
The controversial municipal bylaw in question — known as P-6 — bans wearing masks at protests and requires organizers to submit an itinerary of the demonstration to police before it begins.
Montreal's council adopted the bylaw in the spring of 2012, at the height of the Quebec student protest movement dubbed the "Maple Spring."
Municipal court Judge Randall Richmond acquitted three demonstrators earlier this month, rejecting the itinerary infraction because none of the accused were organizers of the demonstrations.
The judge also blamed police for a bulk-signing of the tickets by officers who did not necessarily observe the alleged violations themselves.
The city said 245 tickets were immediately withdrawn and another 1,700 will be in the near future.
Coderre said the regulation is still valid and remains in effect, but police will have to apply it correctly.
Quebec human rights group, the league for rights and freedoms, welcomed the city's decision Wednesday, saying the P-6 law is "anti-protest."