"Jedem das Seine" is a German translation of an old Greek principle of justice which translates literally into English as "To each his own," but with the idiomatic meaning of "To each what he deserves."
The phrase was made famous by the Roman author, orator and politician Marcus Tullius Cicero (106 BC - 43 BC): "Justitia suum cuique distribuit." ("Justice renders to everyone his due." (De Natura Deorum, III, 38.) De Finibus, Bonorum et Malorum, liber V, 67: "(...) ut fortitudo in laboribus periculisque cernatur, (...), iustitia in suo cuique tribuendo." - "so that fortitude may be seen in hardship and danger, (...) justice in attributing to each his own").
During World War II, the Nazis used the German phrase at the entrance to the Buchenwald concentration camp. The gate reading "To Each His Own" remained in use after the war, when the Soviets occupied the camp and utilized it for the imprisonment of the Nazis themselves.
The phrase is still used commonly as a proverb in German-speaking countries.