Despite firefighters efforts, the blaze destroyed the last two floors of the building.
The remaining floors suffered fire and water damage; the antique furniture was partially saved.
The damage is considerable, restoration work will be significant and long, probably spreading at least 18 months.
The chateau has been closed until further notice.
Just this past December the Chateau had undergone various interior renovations.
Over 80 firefighters from the area battled the flames for several hours.
The Chateau managers took to Facebook to thank all of the participating fire engines and rescue services,
We express our gratitude to the firemen of Divonne, Gex, Ferney-Voltaire, Thoiry, Bellegarde, Bourg en Bresse, Oyonnax, Trévoux, Nyon, Geneva and Geneva airport.