After the war, after release from prison, Peiper worked for both Porsche and Volkswagen, before moving to France, where he translated books from English to German.
In 1974, he was identified by a former Communist resistance member of the region who issued a report for the French Communist Party. In 1976, a Communist historian, investigating the Gestapo archives, found the Peiper file. Peiper received threats that his house would be burned down and his dogs killed. On receipt of these threats, Peiper, sent his family to Germany. During the night of 13/14 July 1976 (Bastille Day), Peiper's home was attacked. In the ruins, Peiper's charred corpse was found. Attackers had thrown firebombs, including at least one Molotov cocktail, at the house to start the fire, which arson specialists found had been set in three locations at once. The police investigation concluded that Peiper had died of smoke inhalation while attempting to save valuables and firing on his attackers. All three of Peiper's dogs had been wounded by the attackers.