Historically the job of American ambassadors posted to friendly countries has been to quietly smooth over disagreements where they arise. The envoys dispatched to Europe by President Donald Trump, however, are increasingly finding themselves at the heart of controversies themselves.

France demanded an explanation Tuesday from Charles Kushner, the American ambassador in Paris, for why he failed to show up when summoned to explain comments made by the Trump administration that France objected to.

The State Department had said it was concerned that “violent radical leftism is on the rise” after the killing of a French far-right activist.

In response, France has barred Kushner, the father of Trump’s son-in-law Jared, from meeting any French officials.

“When these explanations have taken place then the U.S. ambassador in France will naturally regain access to members of the French government,” French Foreign Minister Jean-Noël Barrot told the broadcaster France Info early Tuesday.

Until then, Kushner’s ban “will naturally, affect his capacity to exercise his mission in our country,” Barrot said.

Quentin Deranque, 23, a far-right activist, died from brain injuries last month after he was beaten during left-right violence on the margins of a student meeting in the French city of Lyon.

Seven people have been handed preliminary charges in connection to the death, including an aide to a lawmaker for the leftist France Unbowed (LFI) party, which has condemned the killing.

Last week, the State Department’s Counterterrorism Bureau posted to X that Deranque’s killing “by left-wing militants, should concern us all.”

It added, “Violent radical leftism is on the rise and its role in Quentin Deranque’s death demonstrates the threat it poses to public safety. We will continue to monitor the situation and expect to see the perpetrators of violence brought to justice.”

The U.S. Embassy in Paris reposted that statement on X.

A French diplomatic official told NBC News on Sunday that Kushner had been summoned to the French foreign ministry, the Quai d’Orsay.

“He did not show up,” according to a statement from a senior official at France’s Ministry of Foreign Affairs on Monday.

The comments on Deranque concerned a “tragedy that occurred in France and concerns only our national public debate — which we refuse to allow to be exploited,” the official said. “Faced with this apparent misunderstanding of the basic expectations of an ambassador who has the honor of representing his country, the minister requested that he no longer be allowed direct access to members of the French government.”

Kushner can still “smooth over the irritants that inevitably arise in a 250-year-old friendships” if he shows up to the ministry, the official added.

The American Embassy in Paris did not immediately respond to NBC News’ requests for comment.

Such clashes between U.S. diplomats and their hosts — often ostensibly allies — have become increasingly commonplace.

Trump officials have openly berated their European partners on everything from defense spending and immigration to “freedom of speech” and the allegation that their governments are too liberal and “woke.”

Kushner himself was summoned last August after he accused President Emmanuel Macron of failing to combat antisemitism. Macron called this an “unacceptable statement for somebody who is supposed to be a diplomat.”

In neighboring Belgium, American Ambassador Bill White was himself summoned last week after accusing his hosts of the “unacceptable harassment of the Jewish community.” That was following an investigation of three men on suspicion of performing circumcisions without certified medical training.

Belgian officials strongly denied this, saying circumcisions are permitted under strict health and safety standards. “Personal attacks against a Belgian minister and interference in judicial matters violate basic diplomatic norms,” Foreign Minister Maxime Prévot wrote in a post on X.

Meanwhile Tom Rose, Washington’s man in Poland, said the U.S. would cut ties with a parliamentary speaker who said that Trump did not deserve the Nobel Peace Prize. Prime Minister Donald Tusk responded: “Allies should respect, not lecture, each other.”