While agreements to tackle illegal migration, increase energy security and boost defence co-operation will be welcomed by his own MPs, perhaps Mr Sunak's biggest achievement is a breakthrough in relations with Paris.
After years of strained ties between the Macron government and previous administrations, Mr Sunak's intention to turn over a new leaf has been clear for some time. His display of affection for Mr Macron, whom he referred to as “mon ami”, or “my friend” in French, left no doubt about his goals.
In a sign that the relationship, called “Le Bromance”, is flourishing, Mr Sunak declared his counterpart a “friend of Britain”.
There was backslapping, handshaking and arms around shoulders as Mr Macron greeted his guest at the Elysee Palace in Paris on Friday morning.
The two leaders have many similarities, having both worked in economics before venturing into politics and eventually taking the helm of their respective nations.
They took part in a group discussion with government ministers from both sides and also held one-on-one discussions.
Mr Sunak’s approach to European leaders is markedly different from that of his predecessor Liz Truss and before her, Boris Johnson.
During a joint press conference following the summit, Mr Sunak and Mr Macron displayed a mutual respect that has been at times absent in UK-European relations since Brexit.
“It was not a summit like others. It was a summit of new ambitions,” declared Mr Macron. “Merci, mon ami!” gushed Mr Sunak before adding: “I feel very fortunate to be serving alongside you.”
There was even an offer of “congratulations” from Mr Macron on Mr Sunak's signing of the Windsor Framework with European Commission President Ursula von der Leyen, with the French leader commending his guest's “resolve to re-engage with the EU”.
Earlier, the Prime Minister tweeted to say “it’s great to be in Paris” for the summit between what he called “close neighbours, great friends, historic allies”.
Mr Macron posted a message of his own on social media, saying the destinies of the UK and France are linked.
“Welcome to Paris, Rishi Sunak,” he added.
Mr Sunak referring to his host as a friend marks a shift from Ms Truss’s approach to the French leader. Shortly before entering No 10 last September, she was asked if Mr Macron was a friend; she responded by saying: “The jury is out.”
Rishi Sunak and Emmanuel Macron meet in Paris — in pictures
Stop the boats
Days after unveiling his Illegal Immigration Bill, the UK Prime Minister struck a new deal with Mr Macron on tackling the flow of small boats from France to Britain via the Channel.
It will include the UK funding a new detention centre in northern France and 500 more law enforcement agents patrolling beaches in northern France.
“All underpinned by more drones and other surveillance technologies that will help ramp up the intersection rate,” Mr Sunak said, referring to people trying to cross the Channel illegally.
Speaking at a joint press conference following talks, he said the agreement will also include a new command centre established where French and British officials will work together under one roof for the first time to stop illegal migration. The centre will run 24/7.
Downing Street said the signatories will also work together “upstream” to stamp out illegal migration at the source, with Britain's National Crime Agency engaging with its French counterpart to patrol routes frequented by people smugglers.
More than 3,000 people have already made the perilous sea journey across busy shipping lanes in the Channel so far this year, with almost 46,000 arriving in the UK last year.
Over three years, Britain will contribute about £481 million ($581 million) in funding to help pay for the new measures. This includes £141 million in 2023-24.
Mr Sunak was keen to emphasise the problem of illegal migration is a “shared issue” for London and Paris.
“I have made it one of my five priorities to stop the boats,” Mr Sunak said in a statement. “We are delivering on that priority to stop people coming to the UK illegally.
“Last year, I agreed the largest ever small boats deal with France to increase UK-funded patrols by 40 per cent. This week, I announced measures to ensure nobody who enters the UK illegally can remain here.
“We don’t need to manage this problem, we need to break it. And today, we have gone further than ever before to put an end to this disgusting trade in human life. Working together, the UK and France will ensure that nobody can exploit our systems with impunity.”
Low-carbon energy co-operation
The first bilateral summit between the UK and France since 2018 also produced “an ambitious new energy partnership” in which the two nations will share ideas on alternatives to fossil fuels.
Mr Sunak said the deal will help the countries ensure that “never again can the likes of [Russian President Vladimir] Putin weaponise our energy security”.
The deal on civil nuclear energy co-operation includes an agreement through which Paris will “examine the case for new energy interconnectors” and a commitment to work together on low-carbon energy, he added.
“Together, I believe we are creating a future where every watt of energy powering our homes and industry will come from secure, sustainable and reliable sources,” Mr Sunak said.
The Prime Minister said he was “confident” the UK and France will be able to get the public “cheaper, more secure, more renewable and cleaner energy, faster” following Friday’s summit.
United in defence
Mr Sunak will also arrive back in Britain with a fresh defence pact under his belt.
He and Mr Macron agreed to strengthen military co-operation in the face of Russia’s war in Ukraine, through which the British and French armies will jointly train Ukrainian marines.
Mr Sunak said the initiative would give Kyiv “a decisive advantage on the battlefield” and help it to win the war.
Increasing interoperability between British and French forces and bringing both sides together for weapons developments are also hallmarks of the deal announced on Friday.
The British and French navies will also co-ordinate carrier deployments to the Indo-Pacific region under the deal.
Mr Macron emphasised the historical ties between his nation and the UK, saying they share a past “that binds us”. He added that the summit represented a reunion and reconnection of long-standing partners.
The French President said the war in Ukraine has placed “new responsibility” on European nations and that the two countries — both members of Nato and permanent members of the UN Security Council — would work together to “build concrete solutions for our future”.
“We share the same assessment, the same resolve: Russia cannot and will not win this war,” he said.
He added that the efforts of France and its allies aim to ensure the war “doesn't spread globally”.