The 2012 outbreak in Quebec City killed 14 people. More than 180 others became ill from bacteria that was found to be in a cooling tower of a downtown office building.
The lawsuit alleges public health director François Desbiens failed to inform the public quickly enough about the outbreak.
It cites the building's owner, the CSQ union federation, for failing to properly clean its cooling towers.
It also says the government failed to prevent the outbreak because it did not act on recommendations following a smaller outbreak in 1996.
At the time, public health officials recommended creating a registry of all buildings with cooling towers.
The suit is claiming $50,000 for people who fell ill, $140,000 for surviving spouses, and $30,000 for victims' children.
"This gives me hope that finally things will be settled," said Nadia Champagne whose father died in the 2012 outbreak.
"It's the best news I could get. I'll be able to have some closure."
Brigitte Arbour's mother died in her arms. She says the class-action lawsuit is too little, too late.
"I didn't expect anything," said Arbour. "If there's a suit, fine. If not, too bad. Whatever the outcome, it won't bring my mother back."
The class action still has to be approved by a court.