Short answers, pulled from the story.
Losses on both sides totaled around 20,000 men according to some sources. Dr Stubner argues that French casualties were significantly higher than Coalition losses and states the allies lost between 11,000 and 14,000 soldiers.
Marshal Michel Ney became confused during the critical moments of the battle on the 21st of May 1813. His faulty positioning allowed the Coalition army to slip through encirclement while he decided to seize a village instead of blocking the retreat path.
General Geraud Duroc suffered mortal wounds from a cannonball on the 21st of May 1813. He was Napoleon's close friend who served as Grand Marshal of the Palace and died shortly after being wounded during the fighting.
Napoleon later called this outcome a missed opportunity given his numbers because his numerical advantage did not translate into decisive strategic results. The disagreement over exact figures remains unresolved among historians today but the French failed to crush the Prusso-Russian army despite their superiority.
Napoleon agreed to a nine-week truce requested by the Allies on the 2nd of June 1813. The Armistice of Pläswitz was signed on June 4 and lasted until July 20 initially before extending through August 10.