Juan Romero, who was born in Córdoba in 1919, was a teenager when the Spanish civil war broke out and went on to fight for the republicans in some of the bloodiest battles of the conflict, including the Battle of the Ebro, where he was wounded.

After crossing the border into France alongside 500,000 fellow republican exiles in 1939, Romero joined the French Foreign Legion. He was captured by the Nazis in the summer of 1940 and eventually sent to Mauthausen, where 5,200 “stateless” republican Spaniards were murdered or worked or starved to death.

Among his enduring memories of Mauthausen was the arrival of one little girl among a group of Jewish prisoners.

“She smiled at me; the poor thing didn’t know she was going to the gas chamber. I would have hugged her, but if I did, the SS would have sent me in there as well,” he told France 24 last year. “I’ll never forget that moment. It really troubled me; they killed them every day, but that poor kid was innocent.”

It was not until this year that Spain acknowledged his extraordinary commitment and sacrifices. In August, the deputy prime minister, Carmen Calvo, travelled to Romero’s home in Ay, north-east France, to present him with a certificate recognising both his persecution and Spain’s outstanding debt.