Henry Rousso was due to take part in a discussion "Writing in dark times" at Texas A&M University when he was stopped last week.
He says it was the first time in 30 years of traveling to the US that he experienced any problems on entry.
Ruosso says an immigration officer told him he wasn't "allowed to give a lecture and receive an honorarium" with his tourist visa. The US State Department allows foreign nationals to receive an honorarium under a tourist visa if they are a lecturer or a speaker and under certain guidelines, all of which Rousso met.
"He is shaken," said Richard J. Golsan, director of the Center for Humanities Research at Texas A&M, who invited Rousso to the conference.
"At this point he loves this country but is frankly disturbed about what is going on. We asked him if he saw this was a result of the new immigration ban. He said he thinks this is the new spirit for immigration, much more suspicious and frankly a hostile take on these things."
Golsan, who invited Rousso to the conference, told CNN an Immigration and Customs Enforcement (ICE) agent called him to corroborate Rousso's story.
"My own experience talking to the agent was unsettling," he said. "All he had to do was Google 'Henry Rousso' and he could see he is who he claimed to be."
Rousso specializes in the study of the World War II and post-war period.
"He was born in Egypt and left Egypt under extremely painful circumstances because he was Jewish. This reminded him of those traumatic experiences," Golsan said.
Golsan notified Texas A&M lawyers and the French Consulate after Rousso told him that he was being "deported." When they intervened, Rousso was told his detention had been a mistake and he was allowed to enter the US.
News reaches France
"We deplore this incident and we hope that the American authorities will remain attentive to the conditions of circulation of our French citizens, who, as in the case of Professor Rousso, contribute to the vitality of relations between France and the United States," the French Foreign Ministry told CNN.
French presidential Emmanuel Macron weighed in on the story, tweeting on Sunday, "There is no excuse for what happened to @Henry_Rousso. Our country is open to scientists and intellectuals. #WelcomeToFrance."
Fellow historian, and CNN contributor, Ruth Ben-Ghiat paid tribute to Rousso on Twitter, saying his work on the cost of forgetting the past is "so relevant."
'A welcoming nation'
ICE said it would not comment on an individual case but said, "The United States has been and continues to be a welcoming nation." It added: "Applicants for admission bear the burden of proof to establish that they are clearly eligible to enter the United States. In order to demonstrate that they are admissible, the applicant must overcome all grounds of inadmissibility."
In a blog post
about his experience, Rousso alluded to Donald Trump's comments about Paris at CPAC
last week. Rousso wrote, "I heard recently that 'Paris isn't Paris anymore.' The United States seems no longer quite the United States."