From a favorable round of Wikipedia Roulette, we tell the story today of a guy going by the name of Oskar Daubmann.
Right off the bat, let's repeat that: going by the name of Oskar Daubmann. The real Daubmann had been killed in World War 1; if the Polish translation from here is to be trusted, he died in 1916 in Grandcourt, France; it is, however, possible that this isn't totally correct and Daubmann had simply been rendered one more unknown body among the hundreds of thousands killed. His soldier's passport, however, had found its way into a second-hand jacket, where in a shop in Offenbach, a petty thief named Ignaz Karl Hummel noticed it in 1932. An alias was always good to have, so he grabbed it.
To match the ID, Hummel concocted a story where he was captured at the Somme and spent the next 16 years in POW camps in France and Algeria while being tortured, starved, and kept in solitary. On his second escape attempt, according to his claims, he walked for 3,000 miles before coming across an Italian steamer headed to Naples. Once in Italy, to add the small bit of credibility to the backstory, he sent a letter from Italy to Daubmann's parents asking if they could get someone to help pick him up.
Now, had he just grabbed the ID of some random guy, that'd be the end of the story. But Hummel had grabbed the ID of a World War 1 soldier whose whereabouts weren't definitively known. In addition, France had told Germany that the last of their POW's had been released back to Germany in 1930. Daubmann's sudden appearance in 1932 would contradict this story, and with the Nazis building their power at the time, this could only help them build German anxiety towards their neighbors. So they ran with it.
There was a little hitch, though. Daubmann and Hummel didn't have matching eye colors. In addition, Daubmann had a facial scar whereas Hummel, even after supposedly spending 16 years as a POW and having been tortured, did not. So when Daubmann's parents got a good look at Hummel, they of course...
...wait, this can't be right. It says here they accepted him as their son. Really? They did? Wow. Well then.
Well, if they didn't have a problem, that was the green light to really make hay of Daubmann. There were lectures, awards, talk of a movie, one soldier who had served with the actual Daubmann either accepting him as well or just shrugging his shoulders and cashing in on his association, other soldiers who served with Daubmann somehow accepting him as well, and the Nazis using the appearance as part of their platform to take minority control of parliament in the July 1932 elections.
France, meanwhile, was insistent that this person was not Daubmann, and while they were dismissed by many Germans, others more sympathetic decided to at least look into it. From here, two versions of the story diverge, differing on how Hummel was ultimately caught. One version is rather mundane, with the local police running checks, fingerprinting Hummel, identifying him as Hummel- a career criminal known to German authorities, remember- and taking him into custody. The other version is rather more dramatic, with Hummel's actual father showing up at one Daubmann event and calling Hummel out right then and there.
Either way, he was caught in October 1932-- very close to the next elections in November, as the Nazis were unable to form a government after the July elections. It was a literal October Surprise. They kept control, but lost ground. (The results are almost irrelevant to the larger scope of history, as between then and the next election, the Reichstag burned and everybody knows the story from there. But for sake of reference.)
Hummel was sentenced to two and a half years in prison, but his real punishment came later on. After taking full control of Germany, the Nazis remembered the guy who embarrassed them on a national scale back when they were rising to power. In 1938, Hummel was shipped to Schwabisch Hall, where he would stay in preventive detention until liberated by American forces in 1945. He would remain in town after his release, living there until his death in 1954.
He got a job as a tailor. No word on if that fateful jacket had anything to do with that choice.