After the fall of his cousin Napoleon III and of the Second Empire, Léon retired in Pontoise, France, and died in poverty.

[4] Napoleon had thought for a long time that he was sterile because his wife Joséphine de Beauharnais, who already had two children from a previous marriage, failed to get pregnant.

[4] Napoleon considered adopting Léon, but realized his other illegitimate children would have claim to the crown and therefore abandoned the idea.

[8][2] Writer Gareth Glover stated Léon was "completely unmanageable" in adulthood and became a "hardened gambler", having to go to debtors' prison twice.

[8] He married in Paris on 2 June 1862 Françoise Fanny Jouet (Brussels, 14 January 1831 - Vitz-sur-Authie, 12 May 1899), with whom he had four children live past infancy (sons Charles, Gaston and Fernand; and daughter Charlotte).