Saint-Eustache emergency service spokeswoman Annie Daoust said the incident happened at the Garderie Les Petits Explorateurs, located at 217 Industriel Blvd.
She said they received a 911 call at about 10:30 a.m. on Tuesday.
The Saint-Eustache fire department confirmed all 72 of the evacuees were taken to hospital as a preventative measure.
Two children were overcome by the fumes. Their condition is unknown.
Quebec Family Minister Francine Charbonneau is expected to comment Tuesday afternoon in Quebec City.
In a television interview on French-language network LCN, Charbonneau said all parents with children at the daycare have been notified.
Officials are investigating the cause. No neighbouring businesses were affected.