Quebecor has locked out workers from its printing plant in Mirabel, north of Montreal.
The Teamsters union says the lock-out directly affects 44 press workers, mechanics, electricians and handlers.
However, the union said it's also trying to address payments for 35 workers who were recently laid off because of lower printing volumes and the ending of commercial activities. Another 15 workers were let go last January.
The plant prints a number of newspapers, including Montreal French-language dailies Le Devoir and le Journal de Montreal.
Quebecor said in a news release that it had no other choice but lock out employees after months of negotiations failed to reach a new contract. It is seeking the appointment of a different mediator.
Union representive Denis Fornier says he doesn't understand why the company took such a dramatic action when the two sides aren't too far apart.