Napoleon surrendered to the British and gave up the French throne, ending his reign.
The first mistake he made was the Continental System, which was his policy to prevent trade between Great Britain and Europe. impacting his relationship with Europe leaders and economy.
Second mistake was the Peninsular war. this war inflamed spanish nationalism and weakened France by multiple invasions from Portugal and Spain.
Last mistake was fighting against the Russians, He split his army to attempt to fight on two fronts.
All together he weakened France's economy and any chance to relationships with any Europeans, Russians, Spanish, ect. And he lost almost all of Europe.