On Thursday, the eve of his last day as French ambassador to the United States, Gérard Araud tweeted an analysis of France’s “yellow vest” protests; questions about the use of sanctions as a tool of foreign policy; a U.S.-topped list of national prison populations; and a soothing Monet painting, “to remind us of the simple beauty of the world.”

The range of subject matter was typical for Araud, 66, who became known as the diplomatic dean of social media during his five-year tenure in Washington. He tweeted his tears this week as Notre Dame burned. He has regularly posted his favorite cartoons and tirelessly touted French culture.

He quotes philosophers and is a master of economically worded put-downs. On the night President Trump was elected, he wrote that “a world collapses before our eyes,” an admittedly undiplomatic observation that he quickly deleted — although not before it led the morning news broadcasts at home.

In a recent farewell interview, before moving to private life in New York from the early-20th-century Kalorama mansion that is the ambassador’s official residence, Araud reflected on a particularly turbulent time in Washington. He arrived in 2014, after five years as French ambassador to the United Nations.

“I think I have a great advantage on the Americans,” he said. “First, I am not an American, which means I am not emotionally committed to what is happening in your country. So I believe I can be coldly clinical.”

“Second, I also know what is happening in Europe . . . and our political scenes are compatible.” In France as well as the United States, Araud said, anger and resentment are being translated into nationalism.

Trump, he said, is merely the manifestation of the phenomenon. “I think that too many people are obsessed by the way the president is behaving,” he said. “It would be much more interesting to have a real debate on the social, economic and political crisis of the United States . . . and also the crisis of the Western democracies.”

In some ways, the sharp shift in personality and modes of governance between President Barack Obama and Trump was far more challenging for an ambassador than any policy changes, Araud said.

“I want to emphasize, and when I say this, most of my liberal friends are fainting, that foreign policy between Obama and Trump has a lot of things in common — especially that the two men understood the fatigue of American public opinion for foreign involvements,” he said.

But on the level of a diplomat in Washington, there were adjustments to be made.

“On the one side, you had the president who was, in a sense, the ultimate bureaucrat . . . going to bed every night with 60 pages of briefs, coming back the next morning with answers,” he said of Obama.

With Trump, Araud said, the traditionally chaotic transition period between presidents was exacerbated by the absence of personnel in senior jobs and continual turnover.

“Two months after the election, the people from Paris were telling me, we’re coming over to meet the new guys. I was obliged to say, there are no new guys,” he said. “Four months later, six months later, they hardly believed me.”

He joked to staff, Araud said, “maybe we should rent people to pretend they’re the new guys.”

“On top of that,” he said, Trump “is the opposite of a bureaucratic president,” and “the chain of command, of information up and down, is basically broken. So it’s quite difficult to pick up information or transmit messages” from the administration.

Trump and French President Emmanuel Macron, elected in May 2017, began a bromance that quickly descended into bickering and thinly veiled insults, many of them via Trump tweets. As relations fell apart, “my advice to Paris,” Araud said, “was don’t answer.”

When protests broke out in France last year, Trump tied the complaints of French demonstrators to Macron’s climate change policy, saying they proved that his own decision to withdraw from international climate agreements was right. He retweeted an inaccurate claim that the protesters were chanting “We want Trump.”

While France’s foreign minister quickly advised Trump via Twitter to mind his own business, Macron did not take the bait. “Every European leader has been the target at some moment” of Trumpian tweets, Araud said. “That’s part of this strange period that we are living in.”

France, he said, was “still trying to adjust. We really don’t want to enter into a childish confrontation and are trying to work with our most important ally, the most important country in the world.”