His parents moved to France shortly after his birth due to increasing antisemitism and a worsening economic climate, eventually settling in Paris.

[1] In 1939, the year Germany invaded Poland and war was declared, Wajsbrot gained his school leaving certificate and began training to be a mechanic.

Wajsbrot joined the Communist resistance group Francs-tireurs et partisans - Main-d'œuvre immigrée (FTP-MOI) shortly afterwards and proved to be a key participant in the violent actions they brought against the occupiers.

[2] Six days after his eighteenth birthday, Wajsbrot threw a grenade into a train carriage reserved for German soldiers, causing "undescribable damage" according to an eye-witness.

Wajsbrot's photograph was one of ten featuring on the Affiche Rouge, the iconic Nazi propaganda poster describing the FTP as an "army of crime".