Château-Landon  Château-Landon is a commune in the Seine-et-Marne department in the Île-de-France region in north-central France. The commune contains with-in it the Souppes-sur-Loing quarry, where the bright white travertine stones for construction of the Sacré-Cœur, Paris were sourced. The inhabitants are called "Chatellandonnais or Castellandonnais".