The Russian president is hoping his personal ties with Trump, who regularly touts their good relationship, will at some point yield a softening of the US approach to his country.
Israeli Prime Minister Benjamin Netanyahu met Russian President Vladimir Putin in Paris on Sunday, their first face-to-face talks since the accidental downing of a Russian plane in Syria provoked tensions.
The President has continuously tip-toed around and avoided criticising Putin for interfering in the fundamental democratic processes of the country he is supposed to lead.
Mr Trump is due to visit a different cemetery on Sunday.
French Interior minister Christophe Castaner later said President Trump's security had "in no way been threatened".
As President Trump was arriving at the unity ceremony in Paris on Sunday, a topless woman bearing the messages "fake" and "peace" on her chest threw herself at the president's motorcade as it pulled up to the Arc de Triomphe in protest.
She was hauled away by security along with two others who were stopped on the edge of the famous avenue.
Trump is sitting between his wife, first lady Melania Trump, and Merkel at the event.
The leaders participated in a centennial celebration of Armistice Day, honored in Europe annually on November 11.
French President Emmanuel Macron confronted fellow world leaders with an uncompromising validation of global cooperation, calling on them to work together to maintain peace and avoid the spiral of war that marked the Armistice signed 100 years ago.
Israelis 'kill Hamas commander' in Gaza exchange of fire
Israel and Hamas have fought three wars since 2008, but both sides have shown that they want to avoid another full scale conflict. Hamas accused Israel of sabotaging an emerging ceasefire agreement that was brokered by Egypt and supported by Qatar.
And they heard the commemoration's host, French President Emmanuel Macron, warn about the fragility of peace and the dangers of nationalism - a theme that seemed directed, at least in part, at US President Donald Trump, who listened stony-faced.
Macron's comments on Fareed Zakaria GPS were made after Trump, on a visit to Paris to commemorate the 100th anniversary of the WWI armistice, criticized Macron via Twitter for proposing the creation of a "true European army".
"Because patriotism is exactly the opposite of nationalism".
"Patriotism is the exact opposite of nationalism, nationalism is a betrayal of patriotism", Macron said.
Cameras at the event captured Trump and Putin briefly shaking hands after Putin arrived.
With Trump and other leaders looking on, Macron said nationalism is risky and the "ancient demons" responsible for World War I and millions of deaths are growing stronger.
"We are gathered together at this hallowed resting place to pay tribute to the fearless Americans who gave their last breath in that mighty struggle", Mr. Trump said at the Suresnes American Cemetery and Memorial in the suburbs of Paris, where more than 1,500 Americans who died in the war are buried. He is scheduled to depart for the United States after that.
While praising France for "a wonderful two days", Trump described his rainy stop at the American cemetery at Suresnes as "the highlight of the trip".
An American delegation led by Chief of Staff General John Kelly and Chairman of the Joint Chiefs of Staff Joe Dunford did visit the Aisne-Marne American Cemetery and Memorial under gray skies and drizzle, paying respect to the almost 2,300 war dead buried there.