The US president arrived in France in time for Bastille Day celebrations and the 100th anniversary of American involvement in World War I.
France has rolled out the red carpet to welcome Donald Trump on a presidential visit laden with military pomp that the White House hopes will offer respite from a growing scandal back home.
The US president's brief 24-hour trip to the French capital coincides with celebrations for Bastille Day, France's national day which is marked on Friday, and the 100th anniversary of US involvement in World War I.
Accompanied by First Lady Melania Trump, the 71-year-old stepped onto French soil for the first time as president hoping the visit will distract from weighty allegations that his family and inner circle colluded with Russia to win the 2016 US election.
The scandal has put his son and top aides in legal jeopardy, cast a pall over his efforts to remake the political agenda and may yet imperil his presidency.
During the brief visit, Trump - who sees himself as a transformative figure in US history - will be the guest of honour for Friday's Bastille Day festivities that mark a pivotal point in the French Revolution.
This year's event - featuring 63 planes, 29 helicopters, 241 horses and 3,720 soldiers - also coincides with the centenary of America entering World War I.
More than 50,000 Americans died in what then-president Woodrow Wilson described as the "war to end all wars," a conflict that forged the trans-Atlantic alliance in steel.
Eiffel Tower dinner
On the eve of the parade, Trump will visit Napoleon's tomb, hold talks with French President Emmanuel Macron and share a Michelin-starred dinner atop the Eiffel Tower.
Talks between the two leaders are expected to focus on joint efforts to combat the Islamic State group in Iraq and Syria, where American and French troops are in action side-by-side.
Macron, 39, is hoping to use the weight of history and French grandeur to charm the unpredictable Trump.
But it remains to be seen whether the all the frills and delicate cuisine of acclaimed chef Alain Ducasse will woo this steak-and-ketchup president.
Trump may struggle to stop his mind wondering back to explosive emails in which his oldest son Donald Trump junior appeared to embrace the offer of dirt on Hillary Clinton from Russian interlocutors.
Shortly before leaving Washington, he had to parry criticisms that his administration was in disarray and his legislative agenda on the rocks.
"The W.H. is functioning perfectly, focused on HealthCare, Tax Cuts/Reform & many other things. I have very little time for watching T.V." he tweeted.
Point of convergence?
In London, Berlin, Brussels and Paris, European leaders are wondering how best to handle the US president, whose nationalist "America First" agenda has upended transatlantic relations.
There are already tensions over climate change and trade, while Trump was openly critical of the EU last year and snubbed a handshake with German Chancellor Angela Merkel during their first meeting in March.
"The Western world is fracturing since the American election," Macron said in an interview with regional newspaper Ouest-France published on Thursday.
Trump and Macron appear to have little in common, with their views at odds on everything from globalisation to immigration.
Macron was even described as the "anti-Trump" during his run for the French presidency this year and is half the US president's age.
"It's very difficult to play chess with a man whose strategy is a complete mystery and whose only consistency is his pursuit of American national interest," foreign affairs expert Bertrand Badie of Sciences Po university in Paris told AFP.
"To imagine that you might change his mind on something is simply mad."
Macron also told Ouest-France that Paris and Washington had "an essential point of convergence: fighting terrorism and protecting our vital interests".
However, he also lamented "a protectionist tendency (which) has resurfaced in the United States".
"I want to defend free and fair trade," he added.
French charm offensive
Sources at the White House and in the French presidency insist ties are healthy even after a muscular handshake seen as a battle of wills between the two of them when they first met at a NATO summit in May.
"The relationship is excellent," said one member of Macron's team.
Objections against Trump's visit to France have so far been muted, with the government insisting on the need to build bridges with the White House and avoid Trump becoming isolated internationally.
"What Emmanuel Macron wants to do is to bring him into the circle, include him in discussions," government spokesman Christophe Castaner said Thursday.
"If France can play a role as a facilitator, I'm proud that Emmanuel Macron can contribute to that."
Part of the charm offensive is a packed agenda for first ladies Melania Trump and Brigitte Macron.
The US First Lady - decked in a red skirt suit and heels - on Thursday morning visited a sprawling children's hospital in central Paris.
Nearly 11,000 police officers will be on duty, with France in its highest state of alert after a string of terror attacks since 2015 that have killed more than 300 people.
And in early July, police charged a 23-year-old suspected far-right activist with plotting to assassinate Macron at the Bastille Day parade.
It is also just one day shy of one year ago when on July 14 the country was plunged into mourning again after a truck ploughed into families enjoying a fireworks display in the southern Riviera city of Nice, leaving 86 dead.
The IS group claimed responsibility.