In France in 1852, voters were asked whether they approved of the re-establishment of the Empire in the person of Louis Napoléon Bonaparte,  the only president of what republic?
Napoleon III Louis-Napoléon Bonaparte (born Charles-Louis Napoléon Bonaparte; 20 April 1808 – 9 January 1873) was the President of France from 1848 to 1852 and, as Napoleon III, the Emperor of the French from 1852 to 1870. He was the only president of the French Second Republic and the head of the Second French Empire.
Francis II, Holy Roman Emperor Francis II (German: "Franz" ; 12 February 1768 – 2 March 1835) was the last Holy Roman Emperor, ruling from 1792 until 6 August 1806, when he dissolved the Holy Roman Empire of the German Nation after the decisive defeat at the hands of the First French Empire led by Napoleon at the Battle of Austerlitz. In 1804, he had founded the Austrian Empire and became Francis I, the first Emperor of Austria, ruling from 1804 to 1835, so later he was named the one and only "Doppelkaiser" (double emperor) in history.