Chateauguay Mayor Nathalie Simon is being hailed by police authorities for reporting an alleged attempt to bribe her for a sum believed to be $31,000.

The mayor informed the police of the offer of cash in exchange for political favours, thus helping Quebec's anti-corruption police to arrest former councillor René Lafrance, his son Eric Lafrance, contractor Michel Bergevin and Jacques Roy.

Simon said the men offered "tens of thousands of dollars" in an attempt to win a crucial job within the city's administration and also to greenlight zoning changes that would benefit a local developer.

Instead of accepting their illegal offer, she called police to report the crime.

UPAC commissioner Robert Lafreniere said he was baffled that anyone would attempt to bribe city officials while the Charbonneau commission into corruption in the construction industry was in full swing.

"I particularly wanted to tell you about this case because we have benefited from the extraordinary yet exemplary co-operation of an elected official," said Lafreniere.

"Nothing can be held against Ms. Simon. To the contrary she honourably denounced an unacceptable situation."

Simon - who fired Roy after she was elected in 2009 -  told CTV Montreal that she always made a point of reporting anything unusual to police. Sharing information about the alleged bribe attempt was just part of that.

"It was a normal decision because since I've been elected, every time I find something weird or irregular, I talk with my police officers about it. I tried to send everything that I found to be weird to the proper authorities," she said.

All four suspects have been released from custody under a promise to appear in court in the near future. A sum of $31,000 was also seized in the investigation, presumably the money that the men allegedly attempted to bribe the mayor with.

They will face charges of conspiracy, influence peddling, and other crimes.

Authorities also announced their intention to beef up security around the mayor following the revelations.