The French authorities said the academic had been traveling to a conference near Houston when border officials blocked his entry because of conversations found on his phone.

Philippe Baptiste, France’s higher education and research minister, said he “learned with concern” that a French researcher who had traveled to the US on assignment for the National Ventre for Scientific Research “was denied entry to the United States before being expelled” in a statement to Agence France-Presse (AFP) reported in Le Monde.

A French scientist was denied entry to the United States this month over messages critical of President Trump’s administration’s research policies, according to France’s government.