The Labortoire de Recherche des Monuments historiques is concerned with problems of restoration, and also with obtaining information about techniques. Wall paintings from 15 buildings, dating from the Carolingian period to the Renaissance (9th to 16th centuries) were examined. The wall paintings show 3 types of stratigraphy; color on mortar; color over intonnacco on mortar; or 2 color layers on mortar. Pigments were identified by microtests by the method of G. Charlot; they red iron oxide, minium, vermilion, yellow iron oxide, unidentified yellow, iron earth, copper green, azurite, lapis lazuli, smalt and chalk. The medium will be studied by infrared spectrophotometry.