The Rothschild family signed a letter of intent on Wednesday to sell the Dutch government a Rembrandt self-portrait for €165 million ($187.1m), the Culture Ministry said.
The Dutch master's The Standard Bearer will be "in Dutch hands for the first time" if Parliament backs the initiative, ministry spokesman Michiel Hendrikx said.
Mr Hendrikx said he was confident that MPs would support the purchase.
"It's a unique opportunity" to acquire a last Rembrandt of such quality, he said, expressing satisfaction that the Netherlands had "managed to seize it".
Paris said on Tuesday that it would allow a sale on the open market even though the work, which is valued at €165m, is classed as a "national treasure" in France.
If the Dutch Parliament approves up to €150m in funds, the Rembrandt Association would add €15m and the Rijksmuseum €10m.
"The Standard Bearer is one of Rembrandt's absolute masterpieces and inextricably tied to the history of the Netherlands," the Culture Ministry in The Hague said.
The work "was in private hands for centuries, including the king of England, and since 1844 the Rothschild family", it said.
Rembrandt was 30 when he painted the work in 1636.
"The Standard Bearer is coming home for good after a journey of several centuries," Netherlands Culture Minister Ingrid van Engelshoven said.
Taco Dibbits, director of Amsterdam's Rijksmuseum, which hosts 22 of Rembrandt's about 340 paintings, said: "We have been dreaming for generations of bringing The Standard Bearer to our country.
"The quality and the fact that this painting marks Rembrandt's breakthrough as an artist make it an unmatched work from the master."
Meanwhile, also on Wednesday, a sketch that has been hidden for centuries under the thick layers of paint Rembrandt applied to create The Night Watch offers new insight into the Dutch master's creative process, museum officials said.
Mr Dibbits called the discovery a "breakthrough" in the understanding of Rembrandt's most famous work.
"We always suspected Rembrandt must have made a sketch on the canvas before embarking on this incredibly complex composition, but we didn't have the evidence," he said
The sketch reveals that the artist initially planned to paint feathers on one militiaman's helmet, and that he decided against including a sword that he had drawn between the two main figures.
"On the sketch the feathers are clearly visible, on the painting not," said Pieter Roelofs, the Amsterdam museum's head of paintings.
"Why did Rembrandt change his mind? We don't know. But probably he removed the feathers because they drew too much attention as Van Cruijsbergen [the militiaman] is in the centre of the painting."
About 30 experts have been working on the 1642 masterpiece for two and a half years using cutting-edge imaging techniques and computer technology.
The Rijksmuseum on Wednesday unveiled the findings of a first phase of the project aimed at understanding the artist's technique and restoring the huge work to its original brilliance.
"It is fascinating to see Rembrandt searching for the right composition" of the work, which is 3.8 metres high and 4.5 metres wide, and weighs 337 kilograms, Mr Dibbits said.
"We have discovered the genesis of The Night Watch."
Rembrandt van Rijn painted The Night Watch after a commission by Frans Banninck Cocq, the mayor and leader of Amsterdam's civic guard, to depict the officers and other members of the militia.
Since the project began in July 2019, millions of visitors have been able to watch the historic restoration work at the Rijksmuseum, where it is protected by a glass casing in the centre of the museum's main gallery.
The painting has suffered many travails over the centuries. In 1715, large chunks of the work were sliced off the edges so that it could fit into a new venue.
Thanks to a reconstruction based on a small 17th-century copy, the missing sections were restored to the work using artificial intelligence this year.
The painting was stabbed by a man with a knife in 1911, was hidden in a bunker when Nazi Germany invaded the Netherlands, was slashed by another knifeman in 1975 and then sprayed with acid in 1990.
The multimillion-euro Operation Night Watch is the most extensive research and restoration project to tackle the masterpiece.
In the next phase, which begins on January 19, experts will study deformations in the painting's upper left corner.
They will also decide whether to carry out a complete or partial restoration.
"In many areas the paint is still in an excellent state," the museum said. It said other areas "are in poor repair ... It is more than likely ... that the removal of varnish in the past led to the dissolving of paint at some locations".
Mr Roelofs said: "The condition of the painting is what you would expect from an almost 400-year-old painting, but nowhere does the condition set alarm bells off."
