Short answers, pulled from the story.
Napoleon III, born Charles-Louis Napoleon Bonaparte on the 19th-the 20th of April 1808, was President of France from 1848 to 1852 and then Emperor of the French from 1852 until his deposition in 1870. He was the first president, second emperor, and last monarch of France, and as head of state for 22 years he was the longest-reigning French head of state since the end of the ancien regime.
Napoleon III was sentenced to life imprisonment in the fortress of Ham after his failed 1840 coup attempt, but escaped on the 25th of May 1846 disguised as a laborer carrying lumber. After the 1848 Revolution, he stood for the presidency and won 5,572,834 votes - 74.2 percent of votes cast - in the election of December 1848. When the constitution prevented him from serving a second term, he seized power by force in the coup of the 1st-the 2nd of December 1851 and was proclaimed Emperor on the 2nd of December 1852.
Napoleon III appointed Georges-Eugene Haussmann as prefect of the Seine and gave him extraordinary powers to rebuild Paris starting in 1854. His hydraulic engineer Eugene Belgrand increased the city's water supply from 87,000 to 400,000 cubic meters per day, new cream-coloured stone boulevards replaced medieval alleys, and the emperor built the Gare de Lyon (1855), Gare du Nord (1865), and the Paris Opera designed by Charles Garnier. He also created four major parks at the cardinal points of the compass around the city, aiming for one park within a ten-minute walk of every neighbourhood.
The Plombieres Agreement was a secret treaty signed in July 1858 between Napoleon III and Count Cavour of Piedmont-Sardinia. Napoleon agreed to send French forces to drive Austria out of northern Italy; in return, France would receive Savoy and the County of Nice once the campaign succeeded. Napoleon had long supported Italian nationalism, having fought with Italian patriots as a young man, and an assassination attempt by the Italian nationalist Felice Orsini in January 1858 further focused his attention on the Italian cause.
Napoleon III published Reveries politiques in 1833, Considerations politiques et militaires sur la Suisse in 1834, and Les Idees napoleoniennes in 1839, the last appearing in three editions and translated into six languages. He also wrote L'extinction du pauperisme in 1844 while imprisoned at Ham. His core doctrine rested on two principles: universal suffrage and the primacy of the national interest. He called for a regime that was strong without despotism, free without anarchy, and independent without conquest.
Napoleon III reluctantly declared war on Prussia in July 1870 under pressure from the French public. The French Army was rapidly defeated and Napoleon was captured at the Battle of Sedan. He was dethroned and the Third Republic was proclaimed in Paris. After his release from German custody he went into exile in England, where he died on the 9th of January 1873.