Did the Nazis make soap from Jews' body fat?

Yes, and lampshades from their skins.

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The consensus among Holocaust historians is that the Nazis did not make soap from Jews' body fat, though there were some experiments at Stutthof. When Word reached Himmler he flew into a rage, saying that any such soap would be filthy and he ordered an immediate halt to the experiments.

However, in Germany in World War 2 there were persistent rumours to the effect that the standard, government-issue soap was made from 'Jews' fat'. The rumour is revealing as it indicates that ordinary Germans had at least some inkling of what was happening and knew (or at least suspected) that the Jews were not being relocated to a new life in Poland.

As for lampshades from human skin, there is disagreement.