Eight people have been arrested after France's First Lady Brigitte Macron's great-nephew was attacked on Monday following a TV address by the French president.
Jean-Baptiste Trogneux was beaten up by anti-government protesters in the northern city of Amiens.
He was hit on the head, arms and legs and is awaiting the result of a scan.
President Emmanuel Macron has called the assault "unacceptable", adding that "violence has no place in a democracy".
Jean-Baptiste Trogneux was attacked outside the family chocolate shop in Amiens, which has repeatedly been targeted by protesters.
Local police say they have arrested eight people after the attack.
The attackers fled the scene after neighbours intervened to stop the assault.
Speaking on Tuesday, Ms Macron said she was in total solidarity with her family and condemned the "cowardice, stupidity and violence" of the attack.
"I have repeatedly denounced this violence, which can only lead to the worst," she said.
Jean-Baptise Trogneux's father, Jean-Alexandre Trogneux, told French media the attackers "crossed the line" and insulted "the president, his wife and our family".
"I'm flabbergasted," he added.
The president of the Republicans party, Eric Ciotti, has condemned the attack and called for the attackers to be punished.
"Yes to democratic debate, no to violence and terror," he wrote in a tweet.
The family of Brigitte Macron has run the Jean Trogneux chocolate shop in Amiens for six generations. It specialises in Amiens macarons, a sugary almond-based treat.
The Trogneux family business - which has shops across northern France - has repeatedly been targeted by protesters since Mr Macron has been in office amid rumours that the first family has a financial interest in the company - which it denies.
Jean-Alexandre Trogneux told the Courrier Picard newspaper he did not understand why his family business was targeted.
"Emmanuel Macron has got nothing to do with our business," he said. "I don't understand all these people who continue to hassle us. Some of them even call for boycotts of our shops and products," he told the paper.
Mr Macron has faced some of the biggest demonstrations in a generation over his reform to the pension system, which is set to raise the retirement age from 62 to 64 later this year.
The unrest has seen one of the president's favourite restaurants in Paris set alight as well as attacks on offices of local and national politicians.