They were apparently killed by a high concentration of carbon monoxide gas - possibly caused by a fire lit by the teenagers.
The dead were named as Pierre Lamperrier, 14, and brothers Nicolas, 14, and Thomas Have, 13. The alarm was raised late on Wednesday when the brothers' father failed to return after going looking for them in the tunnels, outside the village of Buchy near the port of Rouen.
The search turned into another tragedy. A fire brigade medical captain and a villager were overcome by fumes and died. Three other fire brigade members were brought out ill before the search was suspended to blow the lethal gas out of the galleries during the night.
Another rescue squad, equip-ped with breathing apparatus, went in on yesterday morning. They brought out a seriously ill fire brigade member and found the bodies of the youths, the father and three more rescuers.
A judicial inquiry is to be opened into the accident.Reuse content