The children were discovered by the father who raised the alarm, a source at the gendarmerie told AFP.
Dispatched to the site around 12:30 p.m., the emergency services could only note the deaths, said the firefighters, confirming information from Dauphiné Libéré.
According to the regional daily, the man who discovered the bodies is the father of the youngest child.
Around sixty gendarmes and a helicopter are mobilized for the search, a source close to the investigation told AFP.
The three children had stab wounds, according to the daily Le Parisien.
Taninges is a commune of 3,500 inhabitants in the Giffre valley, approximately 50 km east of Geneva.
The Bonneville prosecutor, who visited the scene, could not immediately be reached.
Last week, two children aged one and four were found decapitated at their home in Sainte-Rose, Guadeloupe, and the mother, found wandering the streets of the town, was interned in a psychiatric hospital.
According to the National Child Protection Observatory, 60 minors died violently within their family in 2022.
