The centenarian, a member of the Nazi party’s paramilitary SS, is charged with 3,518 counts of accessory to murder after allegedly standing guard in the watchtower at Sachsenhausen concentration camp between 1942 and 1945.
The defendant, named only as Josef S because of German law, has been deemed fit enough to stand trial despite his advanced age, although sessions will be limited to just two and a half hours each day.
Among the crimes prosecutors say he contributed to are the shooting of Soviet prisoners of war and the killing of others with Zyklon B, the poison gas also used in extermination camps where millions of Jews were killed in the Holocaust.
“He is accused of contributing to cruel and insidious murders,” the court in Neuruppin, near Berlin, said in a statement, adding that the man had contributed to “creating and maintaining life-threatening conditions in the camp”.
Recent years have seen a spate of charges brought against now-extremely elderly former camp guards for crimes against humanity committed during the Second World War.
Last week, a 96-year-old former camp secretary went on the run on the day her trial was due to begin, but was caught by police a few hours later.
A 2011 court ruling paved the way to these final prosecutions, stating that even those who contributed indirectly to wartime murders, without pulling a trigger or giving an order, could bear criminal responsibility.
Sachsenhausen, opened in 1936 as one of the earliest Nazi concentration camps, acted as a training camp for SS guards who then went to serve in other camps like Auschwitz and Treblinka.
More than 200,000 people were held at the camp between 1936 and 1945.
Tens of thousands of inmates died of starvation, disease, forced labour and other causes, as well as through medical experiments and systematic SS extermination operations including shootings, hangings and gassing.
Among those killed were Dutch resistance fighters and the Nazis’ domestic political opponents.
Exact numbers on those killed vary, with upper estimates of some 100,000, though scholars suggest figures of 40,000 to 50,000 are likely more accurate.
Additional reporting by agencies