By Sudip Kar-Gupta and Matthias Blamont
PARIS (Reuters) - President Donald Trump watched U.S. and French soldiers march together through the Paris sunshine on Friday in a double celebration marking 100 years since the United States entered World War One and France's annual Bastille Day holiday.
Also featuring a bi-national fly-past of American F16 and French Rafale jets symbolizing military cooperation in the Middle East and elsewhere, the occasion followed a day of talks with French President Emmanuel Macron, a first ladies' tour of Paris, and a dinner for the four at a restaurant in the Eiffel Tower.
"Great evening with President @EmmanuelMacron & Mrs. Macron. Went to Eiffel Tower for dinner. Relationship with France stronger than ever," Trump wrote in a tweet.
The ceremonies brought to an end a visit Macron needs as a boost to France's standing on the world stage - one which could also help a U.S. leader left short of international friends by his stance on free trade and climate change.
Trump, also dogged at home by an investigation into alleged Russian interference in the 2016 U.S. election, appeared on Thursday to leave open the door for more talks on the Paris accord which he pulled the United States out of earlier this year.
Macron arrived standing in a military jeep and surrounded by cavalry - repeating a scene from his inauguration two months ago aimed at reinforcing a message that he heads an important military power.
But it came as a fierce row raged between Macron and his armed forces chief, General Pierre de Villiers, over proposed defense budget cuts that are part of his bid to put the French economy in order.
Trump arrived with his wife Melania in a black sedan to be greeted by French first lady Brigitte Macron.
At the parade, the two heads of state sat together in a stand applauding, pointing and touching each other on the arm as military aircraft flew overhead. Trump saluted as U.S. military personnel - some in World War One battledress - opened the march-past with the Arc de Triomphe in the background.
"Mr. Trump's presence at my side is a sign of an enduring friendship and I want to thank him," Macron said in a speech afterwards. "Nothing can ever separate us... I want to thank America for the choice made a hundred years ago"
By the end of the 1914-1918 war, more than a million U.S. troops were stationed in France alongside soldiers of French, British and other nationalities fighting Germany.
One marching group evoked another military landmark of Franco-American history, carrying a pennant marked "Fregate Lafayette", a frigate of the French navy named after the 18th century French aristocrat general Marquis de Lafayette, who helped in the American Revolutionary War against the British.
For France, this year's Bastille Day has an additional poignancy as the first anniversary of one of the deadliest Islamist militant attacks of the past few years.
After the parade, his first as President, Macron will head for the Mediterranean city of Nice, where he will join a commemoration for the 86 people who died when a Tunisian man drove a truck at a crowd on the waterfront a year ago.
(Additional reporting by Ayesha Rascoe; writing by Andrew Callus; editing by Ralph Boulton)