Enbridge Inc has shut down a crude oil pipeline after protestors locked themselves to equipment at a valve site in Quebec.
The Line 9 crude oil pipeline produces around 300,000 barrels per day.
A spokesman for the company said three protestors had broken into a fenced site about 80km west of Montreal yesterday.
The protestors are alleged to have tampered with a pipeline valve before locking themselves onto equipment.
The pipeline normally runs from Sarnia, Ontario, to Montreal, Quebec.
The protestors, who were eventually removed by police at the scene, said they were concerned an oil spill could contaminate drinking water.
In a statement the group said: “At a time when the climate conference is taking place in Paris, it is urgent to realize that such projects are incompatible with the fight against climate change.”