Marcel Guibord says the charge has "has nothing to do" with his management of the small bilingual municipality, adding he is "totally innocent."
Provincial police say their anti-rackets branch took over the investigation after a complaint was received in August 2011 that emails sent between local politicians were being illegally intercepted.
Police say while that probe found no criminal offence occurred, an examination of the contents of the emails have led them to charge three city politicians and a lawyer.
An OPP spokeswoman declined comment, but Coun. Michel Thivierge says the emails were regarding a move by city officials and an individual outside the government to terminate the contract of the municipality's chief administrative officer.
Charged with breach of trust are Guibord, Coun. Guy Felio, Coun. Diane Choiniere and Stephane Lalonde, who is additionally charged with counselling to commit breach of trust.
Police say all four have been released and are due in a L'Orignal court on Oct. 23.
Attempts to reach Lalonde through his Clarence-Rockland law office Wednesday were not immediately returned.
Guibord said he is eager to contest the charge.
"I know that I am totally innocent and, what can I say, I'm very happy to live in Canada because we are always innocent until proven otherwise. And we are going to go to court," Guibord said.
"I don't have to step out. What's happening right now has nothing to do with my management, or the management of the two councillors" also charged, he added.
Thivierge said the termination of the administrative officer's contract following the city's 2010 election has outraged residents and cost more than $370,000, which he says required a tax hike to pay for.