At the Sorbonne, Damais received various graduate certificates: Arabic studies, Indology, and history of religions.
In April 1937, he went to Batavia, as project manager of the Ministry of Education and in Surakarta, where he studied dance, music and Javanese language.
Living in Java during the years of the Japanese occupation, he befriended Dr. Willem F. Stutterheim, head of the Archaeological Service in the Dutch Indies.
It was at this time that he joined the EFEO as general secretary: he moved to Hanoi a year before the school established a research center in Jakarta in 1952.
In 1959, at the Ecole Pratique des Hautes Etudes, in the historical and philological sciences department, he created a management study of Indonesian languages and civilizations.