A teacher was asked to remove his hoodie because it had the word "Islam" on the back - which is his surname - and was upsetting pub customers.
Nurul Islam, 32, was wearing his school sweatshirt, which all have surnames on, outside the Coach and Horses in Newgate Street, near Hertford, on Friday.
A member of staff said it was upsetting people after the Nice attack, he said.
A police hate crime officer is investigating what happened. The pub would not comment.