Quebec's public health authority released its findings of a study into new streetlights proposed by Denis Coderre's government - and found that they don't pose any danger to human health.
The city planned to install 132,000 LED streetlights, which use less energy than high pressure sodium lights, especially old lamps, but put the change on hold until the public health authority had completed an inquiry.
The LED lights have a blue tone, instead of the amber colour Montrealers are used to.
But the science isn't settled on the question of the LED lamps, and various researchers have flagged a range of health effects that the LED bulbs pose.
Robert Dick, a University of Ottawa physics professor and founder of the Canadian Light Pollution Abatement Program, says the more powerful blue tone can interfere with peoples' body clocks.
"With the amount of blue light in the new LEDs the body has trouble knowing whether it is actually night time," Dick explains.
"There's a particular melatonin that enables the rejuvenation process to begin. And if you have illumination in the order of about three to four times the full moon, that's enough to reduce this hormone by about 50 to 60 per cent."
Even if there isn't a streetlight directly outside your window, if large swathes of the city are lit with the same lamps, there is an overall "bubble" of light created.
According to Dick, the body registers the current orange light tone as something much closer to darkness - allowing for better sleep.
"We've evolved to expect and indeed require a dark night, and the blue light that scatters about from [LED lights'] sky glow in the city confuses our senses into thinking it's still daylight, and the rejuvenation that's done at night is disabled or delayed until that light falls below a low threshold."
"If you happen to be living along an illuminated street, it'll never get that dark."
Dick says other research has indicated that the blue LED lights can also increase stress and anxiety, and increase the symptoms of dementia, and it can drive animals to shift their habitats, even in unlit, natural areas outside of the city.
According to Dick, amber-coloured LED lights which would get around the problem are relatively rare on the market, and are expensive.
In a statement to newspaper Metro, Aref Salem, a city councillor responsible for transportation, said that health and safety of citizens is a priority, and that well lit streets are essential for ensuring the security of the public.