The red leather that had held up the French emperor through numerous campaigns gave way and the cinema director-style chair's wooden structure was also damaged, officials at the Museum of Fine Arts in Napoleon's birthplace, Ajaccio on the island of Corsica, admitted on Monday.
The incident actually happened on Thursday but had been covered up until being revealed by local newspapers following an emergency visit by a restoration expert from Grenoble.
"The end result is that the chair has now been very well restored, which it previously had been but less well," said museum curator Philippe Costamagna.
The employee concerned faces a disciplinary hearing.
The chair is part of an exhibition due to run for three months from Thursday featuring the last existing tent used by Napoleon during his military campaigns and a collection of the furniture he used.
