According to historians, around 30,000 people were sentenced to death for desertion or treason by Nazi military tribunals during World War II, and some 20,000 were executed.
Mr Baumann says the men who were described as "wartime traitors" were not traitors at all.
"They behaved humanely. Some hid Jews, others helped prisoners - they followed their moral conscience," he said.
It is a view backed by experts. "These men were not traitors, they were part of the German resistance movement against Hitler," said Johannes Tuchel, the Director of the German Resistance Memorial Centre in Berlin.
