He and his brother served as officers in a cavalry regiment—the Anciens 11èmes Cuirassiers—when Nazi Germany invaded France in 1940. Both were captured by the Nazis close to the Belgian border during World War II. Élie was taken to the prisoner of war campOflag X-B at Nienberg near Hamburg. After being discovered planning to escape, he was taken to Oflag IV-C at Colditz Castle, then to Oflag X-C at Lübeck, one of the toughest POW camps. There, he was reunited with his brother. Despite being persons of Jewish descent, both were treated by the Wehrmacht as captured officers. He was released in early 1944. Elie later recounted that, despite the harsh condition of the prison, he had been treated well and respectfully throughout. While in Colditz, Élie had written to his childhood sweetheart Baroness Liliane Fould-Springer and asked her to marry him, which they did by proxy by 1942—Élie being allowed to take his marriage vows while imprisoned. Her mother thought her foolish to take on the Rothschild name with the Nazis in control of France. However, they were not troubled during the Nazi occupation. The Fould-Springers had extensive interests in Austria, and one branch of the family ownedChâteau Beychevelle, a Bordeaux estate close to Château Lafite in Pauillac in the Médoc.
He built a web of at least 20 secrecy-cloaked trusts in the South Pacific between 1996 and 2003, some of which continued operating after his death in 2007. As documents from the Offshore leaks revealed at least 20 trusts and 10 holding companies were set up for Rothschild in the Cook Islands, with typically opaque names including, fittingly, ″Anon Trust″. The companies have a common shareholder called ″Mandalor Limited″, an equally opaque company based in Saint Vincent and the Grenadines. Élie was a friend of Prince Aly Khan and Gianni Agnelli. In 1954, when Liliane was out of town, Élie was introduced to divorcée Pamela Churchill. According to Élie, "She was sweet, charming and pretty. I wanted to go to bed with her and I did." Nevertheless, Liliane quickly saw off her rival. When the Duke of Windsor asked her: "Which Rothschild is the lover of Pamela Churchill?' she replied: "My husband, Sir". This remark undermined Pamela as much as any other retributive strikes and presently the affair receded. His nephew Éric de Rothschild, son of Alain, took over at Château Lafite-Rothschild in 1974.
Death
Élie died of a heart attack when on vacation at his hunting lodge near the village of Scharnitz outside Innsbruck in Austria. His wife predeceased him in 2003. He is survived by a son, Nathaniel, and two daughters, Elisabeth and Nelly. He is survived by a daughter, Ondine, who bears the family name. His son is married to Nili Limon, the daughter of Mordechai Limon, commander of the Israel Navy in the 1950s.