Francis Hansen is born on 21 May 1922 in Diekirch, in the Grand-Duchy of Luxembourg. He is the first child of Catherine Welter, single mother, who hands him over in the care of her own mother, in Diekirch. Francis, much loved by his grandmother, shared with her a life of dire poverty until the age of five. His mother, Catherine, marries Victor Hansen, who becomes his step-father and gives him his name and adopts him.
Francis goes to live with them in Ettelbruck. His mother gives later birth to two more children, Pierre and Lucie. Francis’s brother Pierre, would also join the Resistance.