He was born in 1912 in Sofia, Bulgaria, in the midst of a Sephardic family and a French nationality. He studied at a French high school and since his childhood was found at a crossroads of nationalities and religions. In 1930 he moved to France with his family. He soon became engaged in the struggles driven by the French Communist Party by participating in the strikes and manifestations of the 1930s.
In 1936, he managed to bring together a group of volunteers who marched to Spain to help the Spanish Republicans. One afternoon in late October 1936, they took the train at Austerliz station and left for Perpignan. Two buses approached the Spanish border that crossed on foot. From his arrival at the Spanish border, he retains the memory of some young men armed with rifles and wrapped in a "sort of cloak that resembled a blanket in which they had made a hole to pass their heads."
This was his subsequent journey in Spain:
-Fortress of Figueras, meeting place of the volunteers of the BI.
-Barcelona, Carlos Marx Barracks.
-Albacete, where he was given a rifle and uniform and became a republic fighter within the Thaelman Battalion of the XII International Brigade.
-Travel by train and bus to Chinchón. He remembered how in numerous seasons the peasants waited on the platforms to greet the brigades.
-Attack on the Hill of Los Angeles: they received the order to help those who fought in Madrid and were surrounded.
-Country house in Madrid.
-Battle of Jarama
-Guadalajara: he was wounded; He was transported to Madrid where he was operated.
-Hospital de Murcia: The leg became infected and had to return to France in 1938.
In 1939 he was mobilized by the French army. After the defeat and capitulation of France, Caesar joined the resistance in the FTP-MOI.