Protests in France may impact the logistics for a planned state visit by Britain's King Charles next week, a Buckingham Palace source said on Wednesday.
"We are keeping a close eye on the situation, and are taking advice from the FCDO and the French side," the source said, referring to the British foreign ministry. "There may be an impact on logistics."
The source said that the visit was not at risk.
President Emmanuel Macron will look to "calm things down" amid growing anger across France over his plans to raise the retirement age.
Rubbish bins and barricades were set ablaze on Tuesday in spontaneous protests in Paris and elsewhere across the country in a sixth night of scuffles with police.
King Charles is due to arrive in France on Sunday for a state visit, his first since becoming monarch.
The visit includes a trip to the Musee d'Orsay art gallery and dinner at the Chateau de Versailles. It also includes events at the Arc de Triomphe before he travels by train to the southwestern city of Bordeaux.
The French presidency said the king's schedule was still being finalised.
Opposition lawmakers have called on Macron to call off the visit given the ongoing tensions across the country.
The daily protests, alongside with rolling strikes that have affected oil depots, public transportation and rubbish collection, notably in Paris, represent the most serious challenge to the centrist president's authority since the "Yellow Vest" revolt four years ago.
"Unbelievable! We are going to have Emmanuel Macron, the monarch who is going to welcome King Charles III in Versailles," Sandrine Rousseau, a senior lawmaker from the Ecologist party said. "Of course he should cancel this visit. Is the priority really to welcome Charles III in Versailles."
Protesters already scuffled with police in Versailles in 2020 over the unpopular pension bill, with riot police blocking their path to the gilded palace built in the 17th century during the reign of King Louis XIV .
(Reporting by Michael Holden, John Irish, Elizabeth Pineau, Dominique Vidalon; Editing by Bernadette Baum and Raissa Kasolowsky)