For two hours before the ceremony, family, friends and members of the community filed into the St. André D'Acton Vale Church, in the Montérégie region, east of Montreal.
"It hurts my heart … they were three angels," said one man who attended the service.
The children — Laurélie, 5, Loïc, 4, and Anaïs, 2 — loved to play at the family-owned tree nursery. As a tribute to their life, tractors from the nursery were parked in front of the church and loaded with stuffed toys left by family members, friends and strangers.
Members of the media were not permitted inside to view the service.
The minister who performed the ceremony said he didn't want to focus on how the children died. He said that a service that revolved around spirituality would be best for the grieving family.
Louise Blanchette, the Aunt of mother Sonia Blanchette, said that today was about being there for the father and the family and supporting them in any way possible.
After the ceremony, the children's father Patrick Desautels, walked out of the church holding onto a photograph of his three children.
He stood on the church steps surrounded by family and friends as dozens of balloons — marked with the numbers 5, 4 and 2 to represent the children's ages — were released into the sky.
Mother charged with first-degree murder
Police discovered the bodies of two girls and their brother at their mother's home last Sunday.
Sonia Blanchette, the 33-year-old mother of the victims, was charged on Wednesday with three counts of first-degree murder.
She remains in police custody and will undergo a psychiatric evaluation to determine if she's fit to face criminal charges.
Her next court appearance is scheduled for Dec. 14.
Last week, the children's father released a written statement asking for privacy for the family.
He said he loved his two daughters and son deeply, and will miss them for the rest of his life.
Neighbours who spoke to CBC News said the mother had lived alone with the three children in the second floor of a duplex for about two years.
CBC News has learned Blanchette lost custody of the children early in 2012 and had been awarded visiting rights once every two weeks, to be supervised by the children's maternal grandmother.
Also on HuffPost