Provincial police will not comment on the inquiry appearance first reported by Radio-Canada, the French-language CBC.
The news organization said police delivered subpoena papers to Rizzuto, who was alleged to have been this country's most powerful Mafia figure and head of a crime family with myriad international ties.
Police confirmed to The Canadian Press that they tracked down Rizzuto on Monday.
"He was met — I can confirm that," said provincial police Sgt. Claude Denis.
"But that's all I can say."
The sight of a prominent underworld figure answering questions on a live TV broadcast would only be the latest twist in an inquiry that has shocked Quebecers, and the country.
Such an event would be extremely rare.
Nearly four decades ago members of the Cotroni-Violi family, whom the Rizzutos violently supplanted, were called as witnesses to the last Quebec inquiry into organized-crime corruption.
The witnesses back then were unco-operative.
"I don't refuse to testify," crime boss Paolo Violi told the 1974 inquiry, in an account described in a book about the Rizzutos, "The Sixth Family."
"I have a lot of respect for the court but I don't have anything to say."
He was slapped with a one-year jail sentence for contempt of court.
Rizzuto has been referred to only in brief snippets at the current inquiry.
Witnesses described meeting him on golfing trips with construction-industry players.
One crooked Montreal civil servant testified that he liked Rizzuto, and found him a charming and entertaining travel companion.
Rizzuto's late father, Nicolo, has played a more prominent role at the inquiry.
Police surveillance footage has shown him stuffing cash into his socks after receiving it from construction bosses.
The inquiry has heard that bid-rigging construction cartels in Quebec drove up the cost of public works with the help of corrupt municipal officials, then shared some of the profits with the Mafia and through kickbacks to the officials and political parties.
The mayors of Montreal and nearby Laval have resigned as a result of the ongoing scandal.
The police surveillance footage of the elder Rizzuto was recorded while Vito Rizzuto was in prison on a decades-old U.S. murder charge.
He was released from a Colorado penitentiary several weeks ago.
During his years behind bars, the Rizzuto family faced a violent putsch. Many of Rizzuto's friends and family disappeared or were killed, including his father and a son who were both gunned down.
Police now believe people loyal to Rizzuto may be behind several retaliatory acts since he was released.