Montreal's inspector general accused former mayor Denis Coderre on Monday of circumventing rules in his handling of last year's Formula E electric race in the city.
Coderre originally wanted well-known entertainment production company evenko to do most of the work on the project.
But evenko concluded the event would lose millions of dollars a year over its first three years.
Coderre's administration then created Montreal It's Electric, a non-profit whose goal was was to obtain government subsidies.
Evenko, at the behest of Coderre's office, became involved in the project as the main subcontractor.
Denis Gallant's report stated Coderre and his office were warned several times by their legal representatives the non-profit should not be used as a a go-between for the city and a private company.
It said the non-profit proved an extension of the city.
"The mayor's office kept control over the decisions made by Montreal It's Electric," Gallant wrote.
"The inspector general concludes that Montreal It's Electric was used to bypass the rules on the awarding of contracts."
Mayor Valerie Plante lambasted her predecessor as soon as the report came out.
"We're elected officials, we are accountable to citizens and what they did was wrong," Plante said.
That wasn't Coderre's take.
"When we put on the event, it was also to promote the electrification of transport," he told Radio-Canada.
"Montreal It's Electric wasn't just about the Formula E race."
In cancelling the race last December, Plante cited cost overruns and sponsorship woes as two of the reasons for the decision.
She said at the time keeping the event in 2018 would cost taxpayers between $30 million and $35 million.
Only 25,000 tickets were sold for last summer's event, which became a hot potato in the fall election campaign that saw Plante defeat Coderre, the driving force behind the race.