PARIS — Henry Rousso is one of France’s most preeminent scholars and public intellectuals. Last week, as the historian attempted to enter the United States to attend an academic symposium, he was detained for more than 10 hours — for no clear reason.

On Wednesday, Rousso arrived at Houston’s George Bush Intercontinental Airport after an 11-hour flight from Paris, en route to Texas A&M University in College Station. There, he was to speak Friday afternoon at the Hagler Institute for Advanced Study.

But things did not go according to plan: Rousso — an Egyptian-born French citizen — was “mistakenly detained” by U.S. immigration authorities, according to Richard Golsan, director of the Glasscock Center for Humanities Research at Texas A&M.

“When he called me with this news two nights ago, he was waiting for customs officials to send him back to Paris as an illegal alien on the first flight out,” Golsan said Friday at the symposium, according to the Eagle, a newspaper that covers the College Station area.

The university then sprang into action, the Eagle reported, with President Michael Young reaching out to law professor Fatma Marouf, who earlier this month had assisted in writing an amicus brief against President Trump’s executive order banning refugees from around the world and travelers from seven Muslim-majority nations.

This is the current process that people with refugee status typically go through to get approval into the country. (Claritza Jimenez, Dani Player/The Washington Post)

Marouf quickly and successfully intervened with immigration authorities, and Rousso was released and allowed to deliver his lecture.

After weeks of headlines related to Trump's travel ban, incident drew immediate attention around the world -- especially in a France on the eve of presidential elections this coming April and May.

Emmanuel Macron, the popular centrist candidate for the French presidency, used the Rousso affair to repeat his pitch to U.S. scientists and researchers who he has said would be better off in France rather than in the America of Donald Trump.

"There is no excuse for what happened to Henry Rousso," Macron wrote Sunday on Twitter. "Our country is open to scientists and intellectuals."

For his part, Rousso confirmed the details of his experience Saturday on Twitter: “I have been detained 10 hours at Houston Itl Airport about to be deported. The officer who arrested me was ‘inexperienced.’”

It remains unclear what about Rousso was identified as suspect by immigration authorities.

Egypt — from which Rousso and his family, as Jews, were exiled in 1956, after a slew of anti-Semitic measures imposed by the administration of President Gamal Abdel Nasser, according to the Israeli newspaper Haaretz — was not among the seven nations in the travel ban, which had been suspended by the time he arrived in the United States.

Furthermore, France is a beneficiary of the U.S. visa waiver program, which permits French citizens to enter the United States without a visa. All that is required is an online ESTA application before departure.

For Marouf, Rousso’s ordeal was indicative of a strict new U.S. border control regime: “It seems like there’s much more rigidity and rigor in enforcing these immigration requirements and technicalities of every visa,” she told the Eagle.

Rousso’s scholarship focuses on the memory of the Vichy regime, the darkest chapter in modern French history, when the government of unoccupied France collaborated with Nazi Germany in World War II. Vichy authorities are particularly infamous for assisting the Germans in rounding up and deporting tens of thousands of Jews from France during the Holocaust, which Rousso once called “the past that does not pass.”

He spoke Friday on a similar subject in College Station, in a lecture titled “Writing on the Dark Side of the Recent Past.”

Fellow historians took to social media after news of Rousso's experience, many pointing out what they considered the uncomfortable irony of the arbitrary detention of a Holocaust historian.

Ruth Ben-Ghiat, a historian at New York University, said on Twitter, “His work on cost of forgetting past (Vichy) so relevant.”

“Thank you so much for your reactions,” Rousso posted Saturday evening on Twitter in response. “My situation was nothing compared to some of the people I saw who couldn't be defended as I was.”

“It is now necessary to deal with the utmost arbitrariness and incompetence on the other side of the Atlantic,” Rousso wrote Sunday in the French edition of the Huffington Post. “What I know, in loving this country forever, is that the United States is no longer quite the United States.”