The Montreal-based company said in a statement Friday it considers the information to be "false and defamatory and published maliciously."
Quebecor Media said it believes the information was "published with the clear intent of tarnishing its reputation."
The Crown corporation says on its website that Quebecor has received more than $500 million in direct and indirect government subsidies in the past three years.
It also says the company uses the public subsidy and its position in protected industries to make record profits, but complains that its TVA television network competes against Radio-Canada.
It adds that Quebecor president Pierre Karl Peladeau has sent more than a dozen letters to the prime minister and others in government to say Radio-Canada does not advertise in his newspapers enough.
The two media giants compete head-to-head in Quebec for television viewers, while Quebecor's Sun Media division frequently publishes criticism of the CBC and has urged an end to its public funding.
In addition to a removal of the comments, Quebecor wants the CBC's French-language service to issue an apology and publish a press release put out by Quebecor on Thursday that aims to correct the CBC statement.
It wasn't immediately clear if Quebecor had set a deadline for the apology or if it had already filed legal action. An email to a Quebecor spokesman was not immediately returned.
A Radio-Canada spokesman said Friday the public broadcaster was not surprised by the letter and will study it before commenting further.
Quebecor's letter came a day after Peladeau appeared at a parliamentary committee hearing into why the CBC is fighting access-to-information laws in the courts.
Radio-Canada says it has been swamped with hundreds of access-to-information requests, mainly from Quebecor's many media outlets, and suspects an orchestrated campaign to damage it.
But Peladeau denied any such vendetta.
"Despite what some may think, in other words, that we are waging a war against CBC-Radio Canada, we believe that these requests are not only legal but also legitimate and in the public interest and in keeping with the act," he told the committee hearing on Thursday.