French war planes fly over the Arc de Triomphe in Paris on Friday before the Bastille Day parade. (Etienne Laurent/Associated Press)

President Trump appears to have enjoyed his time in Paris, a chance to get away from the ever-growing scandal over Russia, his campaign and his eldest son. He basked in the pomp and circumstance, dinner at the Eiffel Tower, the military flyovers and the parade up the Champs Elysées. In the afterglow of the attention that French President Emmanuel Macron lavished on him, Trump even hinted that he might reconsider his decision to pull out of the Paris climate-change agreement.

That goodwill may dissipate once he re-enters the Bannon-Miller reality distortion field that envelops the White House, especially if he missed the whole point of his invitation to France: the 100th anniversary of the arrival of American troops in France during World War I. Because so much of the war took place on French soil, memories of that commitment and how it changed the course of the war remain strong long after the death of the last veteran.

The First World War marked the United States’ decisive debut on the world stage and the beginning of a long romance between the French and the Americans. As happens in relationships, each side left its mark on the other. The French were fascinated by the generosity and the informality of Americans. Many Americans fell in love with France and had their first introduction to camembert and foie gras.

The interaction of black Americans and the French also had a profound effect. Because the American military establishment did not believe Negros could fight, the Allied supreme commander, General Ferdinand Foch, asked to have black soldiers placed under his command. The African American troops proved valiant in combat and in turn were deeply affected by being treated as equals. The taste of life in a society free of Jim Crow laws would serve as inspiration for a burgeoning civil rights movement back home. James Reece Europe’s 369th Infantry Regiment “Harlem Hellfighters” band introduced the French to jazz, igniting a fascination with black Americans and African American artistic creations that survives to this day.

If the international commitment that Americans made a century ago changed their country’s status in the world, they also paid a high price for their leaders’ decision to enter the first global war. More than 4 million men were mobilized and 116,000 Americans died in World War I. France is studded with memorials to the American sacrifice in that war, notably the 14,246 buried in the Meuse-Argonne American Cemetery, the 6,012 in Oise Aisne and the 2,289 in the Aisne Marne American Cemetery.

On Friday, a contingent of American troops joined its French counterpart in marching up the Champs Elysées, a reminder of the leading role that the United States played in international coalitions starting with World War I and that are now threatened by Trump’s “American First” policies. France, Germany and China have all rushed to fill the vacuum left by Trump’s throwback to 19th-century isolationist policies.

The French have low expectations of Trump. A recent Pew survey showed that only 14 percent of French men and women expected the American president to “do the right thing” on foreign affairs. Just days before Trump’s arrival in France, one of the most-watched television talk shows had as its topic, “Trump. A danger to peace?

France’s romance with America has not cooled. Some 73 percent of those polled in the same survey retain a favorable view of Americans. Jeans and T-shirts have become the uniform of young French people, and some French businessmen go to meetings in sneakers. Hamburgers are a hot item in French restaurants — even if the French insist on eating them, as they do pizzas, with a knife and fork.

Despite Trump’s belated affirmation of NATO’s mutual defense treaty, the French, and other U.S. allies, have reason to wonder how far he will go to defend the principles of freedom and democracy that the United States has touted for so long. A visit to the gravesites of Americans buried in France will serve as a reminder of how fiercely we were once willing to fight for these values.

The 100-year-old French-American romance is still deep, and it will survive Donald Trump.