The sale came amid a surge of interest in the rare female baroque painter's extraordinarily dramatic work, and smashed the base estimate of between 600,000 and 800,000 euros.
The painting “Lucretia” depicts the ancient Roman noblewoman who killed herself after being raped, showing her bare-breasted and about to plunge a dagger into her chest.
It was discovered only recently, in a private collection in the southeastern French city of Lyon, where it had been stored unrecognised for some 40 years.
After a “long bidding battle” over the telephone, the painting was sold in Paris for 4,777,000 euros to a European collector, the French auction house said.
It nearly doubled the previous record for her work – 2.8 million euros for a painting of Saint Catherine sold in Paris in 2017.
Detail from Artemisia Gentileschi's Self-Portrait as Saint Catherine of Alexandria.
It is extremely rare for Artemisia works to come on the market.
After years of obscurity, Artemisia (1593-1654) is now recognised as one of the greatest painters of the post-Caravaggio era and one of the few to match the great Baroque master's sense of drama and light.
Her status as of the few female painters of the period has also fuelled a surge of interest in her work and life.
“The interest in older paintings is growing,” said Matthieu Fournier, director of the department of old masters at Artcurial, and art expert Eric Turquin in a statement.
“For the first time we are seeing contemporary art collectors migrate towards classical art”, they added.
Turquin had earlier said the work is “worthy of the great museums of the world” and “comes to us in an exceptional state of conservation”.
In a sign of Artemisia's growing prominence, the National Gallery in London will next year stage the first major exhibition of her work in Britain, bringing together 35 works from around the world.