The diminutive French dictator is said to have rested on the unremarkable, small wooden seat in 1815 at Courcelles in Belgium, 22 miles from the battlefield.
He stayed at the home of a family and the daughter of the owner, Pauline Cambier, kept the chair carefully, aware of who had perched upon it.
It comes with two letters of provenance, one from a friend of Cambier, stating how she had often told him about its history.
He adds: "She had always kept it with greatest care."
Featuring eight stretcher rungs, a rush seat and seven spindles, plus decorative features, it is at odds with the grandeur of the self-styled Emperor who sat on it.
It has had several owners and now is to be sold at auction and collectors from around Europe are expected to bid on it.
Despite his losing the Battle of Waterloo and being humiliatingly sent to exile on St Helena, Napoleon is still revered in France.
The Corsican's empire-building was ultimately ended by the British, notably at Trafalgar and Waterloo, but Napoleana is hugely popular among enthusiasts.
The Battle of Waterloo in June 1815 pitted Napoleon against the Duke of Wellington and his allies.
Though, as Wellington conceded, the battle was "the nearest-run thing you ever saw in your life", the British won, ending many years of war against France.
Richard Davie, of International Autograph Auctions, who is selling the chair, said: "Napoleon is worshipped almost like a god in France.
"Napoleon memorabilia is hugely popular across Europe and that is reflected in the estimate put on this chair.
"It comes with two letters of provenance from the 1920s and it dates from the late 18th or early 19th century."
He added: "It has some wear and a bit of woodworm but remains in good condition and it is quite small - just as Napoleon was."
Napoleon died in exile in 1821 aged 51.
The chair, which is owned by a private collector, is being sold at the Edwardian Radisson Hotel in London this weekend.
