He was accused of writing messages "that reflect hatred toward Trump and can be described as terrorism," and his equipment was seized before he was flown back to Europe the next day.
Philippe Baptiste, France's Minister of Higher Education and Research, voiced his concern in a statement to _AFP_.
"Freedom of opinion, free research, and academic freedom are values that we'll continue to proudly uphold. I will defend the right of all French researchers...while respecting the law," he said.