German East Africa
AD – MPE: 0.2
The Wikipedia-article called “Maji Maji Rebellion” cites estimates for the number of deaths from the war in German East Africa from 1907 to 1908, which range from 0.25 to 0.3 million. Most of the victims died from famine and disease, which were caused in large part by Germany’s scorched-earth policy. I choose 0.2 million as the most plausible estimate for the number of civilians killed by criminal German policies.
Germany was an advanced democracy at the time.