The threats came after Carrier won a coveted contract at the University of Montreal over contractor Francesco Bruno, the commission heard.
The threat, made by Montreal Mob associate Francesco Del Balso, was made public in 2010 by Radio-Canada's investigative program, Enquête.
In January 2004, four days after it was announced that Carrier won the contract, the Quebec City businessman was in his car with his daughter when his cell phone rang.
Carrier's daughter answered the phone.
The person on the other end of the line was Del Balso, who is now serving a prison sentence.
Carrier recorded the conversation, which was played for the Charbonneau commission this morning.
On the tape, Del Balso first confirms that Carrier has done business in Montreal.
Del Balso refuses to identify himself, but then tells Carrier if he returns to Montreal to do business, "you won't leave."
He then hangs up.
Del Balso was a reputed underboss in the Rizzuto crime family. He was arrested with members of the Rizzuto clan in a massive, four-year police operation that ended in raids targeting 70 alleged members of Montreal's Mafia. DelBalso pleaded guilty to a handful of charges including drug trafficking, bookmaking and gangsterism in 2008.
Sympathy card threat
Carrier also told the commission about a card he received in February 2001. The printed message on the sympathy card read:
"Dear Friend! Do not bid on any more contracts in Montreal. You risk seeing your family receive a card identical to this one. LAST WARNING."
Carrier said he believes the card was sent by Bruno, who had called him in 2003 telling him not to bid on the University of Montreal contract. Del Balso called him a few weeks later.