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.

The occasion, also featuring a bi-national fly-past of fighter jets symbolizing military cooperation in the Middle East and elsewhere, 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 bring 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.

Military Prowess

Macron arrived standing in a military jeep and surrounded by cavalry - repeating a scene from his inauguration two months ago and reinforcing the message that he heads an important military power.

The scene also serves as a reminder of a fierce row that erupted this week between Macron and his armed forces chief, General Pierre de Villers, over proposed budget cuts for the defense ministry.

Trump arrived with his wife Melania in a black sedan to be greeted in the sunshine 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 military personnel - some in World War One battledress - filed past with the Arc de Triomphe in the background.

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.