PARIS — A hat belonging to Napoleon Bonaparte when he ruled the French empire in the 19th Century will go on sale at auction in Paris on Sunday.

The bicorne black beaver felt hat is valued between €600,000 and €800,000 (£525,850-£701,131).

Historians say the headwear was part of Napoleon's brand. Wearing it sideways made him recognizable in battle.

He owned around 120 bicorne hats over the years, with only 20 thought to remain — many in private collections.

The hat is being sold along with other Napoleonic memorabilia assembled by an industrialist who died last year.

But the auctioneers said for specialists, the hat is the true holy grail.

The emperor wore his hat with the corns parallel to shoulders — known as “en bataille” — whereas most of his officers wore their hats perpendicular to the shoulders.

Auctioneer Jean Pierre Osenat said: “People recognized this hat everywhere. When they saw it on the battlefields, they knew Napoleon was there.

“And when in private, he always had it on his head or he had it in his hand, and sometimes he threw it on the ground. That was the image — the symbol of the emperor.”

The auctioneers said this hat comes with impeccable provenance, remaining throughout the 19th Century in the same family of the quartermaster of Napoleon's palace.

The hat being auctioned by Osenat auction house in Fontainebleau has a cockade that Napoleon fixed to his hat in 1815, during the crossing of the Mediterranean from his exile in Elba to Antibes, where he led a brief return to power.

Other items being sold include a silver plate looted from Napoleon's carriage after his 1815 defeat at Waterloo and a wooden vanity case he owned, with razors, a silver toothbrush, scissors and other belongings. — BBC