The man was “arrested for questioning” for assault, Bedfordshire Police told AFP.
Charles III, 74, had come to Luton to meet with city officials and local charities and to visit a new Sikh temple.
At the beginning of November, a 23-year-old man had already been arrested in York, in the north of England, after throwing several eggs in the direction of the new monarch, without reaching him, while shaking hands with his admirers in the center of the city next to his wife Camilla.
“This country was built with the blood of slaves,” he would have shouted before being detained by several police officers, at a time when the country is increasingly confronting its slave-owning and colonialist past. Later, he was released on bail.
Last week, the royal family faced a new controversy after a close associate of the late Queen Elizabeth II made racist comments to a black activist during a reception at Buckingham Palace.