In 1840, the year of the return of Napoleon’s remains to France, thirteen or fourteen “Napoleons” were admitted to the insane asylum at Bicêtre in the south of Paris. One can imagine that each of them considered the others to be mad. Of course, there had been people suffering from this kind of delusion even while he was still alive. In 1818, at least five people were admitted to Charenton hospital believing they were Napoleon. Now, however, Napoleon was being caricatured, right down to his temperament — ‘imperial’, proud, haughty, abrupt, tyrannical, capricious, choleric. The men (and one woman that we know of) who believed they were Napoleon always fit the same profile: they took themselves seriously, they gave orders and they demanded loyalty; in return they treated people with disdain.
-- Philip Dwyer, Napoleon: Passion, Death and Resurrection, 1815-1849. Via Marginal Revolutions.