Plante told reporters at city hall she doesn't have a third four-year term in her.

"It is a heartbreaking decision. It was not easy to make because I do love my job," Plante said. "Recently, I came to realize that I couldn't commit to another four years and guarantee Montrealers the same level of energy I've always given."

As well as being mayor of Montreal, Plante is also mayor of the downtown Ville-Marie borough and has served as leader of the Projet Montreal party since December 2016. Plante was first elected to city council in 2013.

Originally from Rouyn-Noranda, Que., she moved to Montreal at 19, where she earned university degrees in anthropology and museology. Her surprise victory at age 43 in 2017 over incumbent mayor Denis Coderre, a former federal Liberal cabinet minister, brought the first woman into the mayor's office. Coderre, sore at being booted after only one term, came back to challenge her to a rematch in 2021 but lost again.

"Our movement is no accident: our ideas or projects reflect the will of the vast majority of Montrealers, and are making waves elsewhere in Quebec," Plante told reporters on Wednesday.

"Projet Montreal is not just one person's party. It existed before me and will continue to evolve," she said.

Plante and her party are recognized for their many projects involving greening the city, transforming major arteries to be more accommodating to cycling, and closing streets to cars to make vibrant pedestrian zones in several districts.

But her party's vision to expand public space for cyclists and pedestrians faced pushback, with critics accusing her and her councillors of being anti-car and pushing their ideas for urban planning without enough consultation from businesses and others who disagreed with them.

She presided over a city that grew rapidly by immigration, including through the addition of thousands of asylum seekers who wanted to make Montreal home but who put pressure on services, especially housing. And like mayors across the country, she faced criticism for a series of social problems relating to homelessness, mental health, and opioids, all aggravated by the COVID-19 pandemic, and that led to a rise in people sleeping rough in tents and on street corners across the city.

Those social ills, coupled with seemingly never-ending construction sites dotting the city, brought her strong -- often unfair -- criticism on social media. Last month, Plante shared screenshots showing insults she had been called on X and defended her decision to turn off comments on the platform and to only allow her followers to comment on her Instagram posts.

Plante's health came under scrutiny in December 2023 when she began feeling dizzy while answering questions at a news conference and had to sit down. Citing fatigue, she returned to her duties after taking a week off to recuperate. On Wednesday she insisted she was in fine health and that she would fully assume her duties for the next 12 months. Municipal elections are scheduled for Nov. 2, 2025, in Montreal and across the province.

Following her announcement, she received numerous tributes on social media, including from Prime Minister Justin Trudeau, who said, "Wishing my friend, Valerie Plante, all the best in her last year as mayor, and in whatever comes next."

Quebec City Mayor Bruno Marchand responded to the news on X, saying Plante's commitment to Montreal has been sincere.

"She has initiated significant changes and has made the entire province of Quebec shine. Every time our cities shine, it is our whole nation that shines as well. Thank you for everything ... it has been a true privilege to share this journey with you."

Quebec Premier Francois Legault said on X, "Her love for Montreal was clear throughout her career in politics."

This report by The Canadian Press was first published Oct. 23, 2024.

-- With files from Sidhartha Banerjee in Montreal.