King Louis XVI was tried because it had become clear by January 1793 that the French monarchy could not coexist and survive alongside the First French Republic and he was found guilt of conspiracy during his reign which resulted to him sentenced of death via guillotine for high treason on 21 January 1793.. His execution three days later, on 23 January 1793, on the Place de la Révolution, formerly the Place Louis XV; the present Place de la Concorde in Paris, made him the only King of France ever to be executed.