In 1910 he gained the Khmer language license and was appointed assistant curator of the Ecole française d'Extrême-Orient (EFEO) Museum in Phnom Penh.
Then he began also excavation and cleaning of other monuments outside Angkor Thom: Ta Prohm (in 1920), Preah Khan, Neak Pean, Phnom Bakheng (1922–29), Prasat Kravan (with Henri Parmentier and Victor Goloubew) and Banteay Srei among others.
[3] In 1930 he went to Java to learn the principles of anastylosis from the archeological service of the Dutch East Indies, aware of the limits of the consolidation methods used previously in Angkor.
In the meantime in 1938, on the way back to France, he visited India and Ceylon, which he described in Souvenirs d'un Conservateur, and before returning to Angkor he led an archeological mission at Arikamedu (called Virampatnam by the French), in Puducherry.
From 1948 to 1953 he directed restoration works on the buildings located along the west roadway of Angkor Wat, the Baphuon (1948), Banteay Kdei, Preah Khan and Thommanon (1950).