The UK will pay France £478 million ($577 million) over three years to beef up measures to stop illegal Channel crossings.
The package will help fund patrols, the use of drones, and a detention centre to stop asylum seekers from travelling to the UK in small boats.
UK Prime Minister Rishi Sunak called the landmark deal an "unprecedented" effort from both nations.
However, French President Emmanuel Macron was reluctant to grant the UK a migration returns agreement that would allow for failed asylum seekers to be returned to France.
This agreement, according to Mr. Macron, would have to be negotiated with the European Union.
Britain has agreed to pay France nearly half a billion pounds to prevent illegal boat crossings across the English Channel, which surged last year.
The deal announced on Friday includes funding a new detention centre in France, employing hundreds of extra French law enforcement officers, and doubling the number of officers deployed to fight crossings.
Both countries will also work together to stop people traffickers along the preferred routes.
UK PM, Rishi Sunak called this "sensible investment" when the UK is spending more than £5 million a day on hotels.
The announcement comes after Sunak's meeting with the French President Emmanuel Macron in Paris, where enhanced efforts by both nations to stop the boats were emphasized.
Sunak believes the major new package will provide value for money for taxpayers.
However, the French President stated that a migration returns agreement, which Sunak covets under his pledge to "stop the boats," would have to be negotiated with the European Union, not Paris.
Details of this historic agreement come after the UK committed over £300 million to France in the last decade to curb illegal migration.