Chaoui says Coderre and other city officials unfairly targeted him and attacked his reputation by calling him an "agent of radicalization."
Lawyer Habib Rachidi says his client has suffered as result of Coderre's comments.
Chaoui has been stopped in the streets and even received death threats, Rachidi said.
"When the head of the second largest city in Canada calls you a threat to public safety and an agent of radicalization, your life is going to suffer," he said.
The dispute began in January, when Chaoui tried to set up an Islamic community centre in the Montreal borough of Mercier-Hochelaga-Maisonneuve.
Ultimately, the borough denied him the permit required to establish his centre, citing zoning regulations.
At a news conference on Jan. 31 explaining the decision, Coderre called Chaoui an "agent of radicalization" who contributed to social tensions.
In March, Rachi sent a letter to Coderre on Chaoui's behalf, asking him to retract statements he made in public — or face a lawsuit.
Coderre ignored the request.
The imam has said that in all his years of preaching, he's never entertained extremist propositions.
"I encouraged young people to pursue their academic studies," he said.
Chaoui previously preached at the St-Jean-sur-Richelieu mosque that Martin Couture-Rouleau attended, but said he didn't personally know the man who killed Warrant Officer Patrice Vincent in a targeted hit-and-run last year.
He has been featured in a number of videos on YouTube and Facebook in which he expressed views sympathetic to Shariah law and in which he suggested that women should have designated guardians.
In his March lawyer's letter, Chaoui said those statements were taken out of context.
He said he supported Shariah law in Muslim countries and that marriage proposals should be presented to women's guardians.
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