The last king of France before the abolition of the monarchy during the French Revolution was Louis XVI. He reigned from 1774 until 1792. After attempts to manage France's escalating crises failed, the monarchy was overthrown, and Louis XVI was executed by guillotine in 1793. His death marked the end of the French monarchy that had lasted for centuries.
However, after the revolutionary period and the fall of Napoleon, the monarchy was briefly restored with kings Louis XVIII and Charles X, and later Louis Philippe I ruled as "King of the French" from 1830 to 1848 before abdicating. The last monarch overall to rule France was Napoleon III, but he was an emperor, not a king.
Therefore, the last official king before the initial and definitive abolition of the monarchy was Louis XVI, though Louis Philippe I was the last monarch with the title of king before the final fall of the monarchy in 1848. For traditional historical reference, Louis XVI is often regarded as the last king of France.
