MONTREAL—Revenu Quebec slapped construction firm Frank Catania & Associates with nearly 1,000 tax evasion charges, millions in fines, and the possibility of jail time for its principal figures on Thursday.

Revenu Quebec handed down 989 charges, $12.5 million in fines, plus the threat of prison over illegal tax credits to 14 individuals and six companies. Construction magnate Paolo Catania and company executive Andre Fortin each face 132 charges over filings that were registered between May 2005 and June 2009.

“This was a major operation against fiscal fraud,” said Robert Lafreniere, head of the province’s anti-corruption squad (UPAC).

It was the second straight day the government agency went after a construction mogul. On Wednesday, Revenu Quebec said Tony Accurso was facing over 900 criminal charges and a tax bill of $8.5 million.

UPAC previously arrested nine people associated with Frank Catania & Associates in May 2012 as part of Operation Faufil, when Catania was arrested as he boarded a plane at Pierre-Elliot-Trudeau International Airport. The construction company has alleged ties to the Sicilian Mafia.