There was widespread rioting in Paris last Saturday, with national monuments including the Arc de Triomphe vandalised and more than 400 people arrested.
Now a spokesman for Mr Macron has told AFP: “We have reason to fear a great violence this Saturday.”
Despite a humiliating government U-turn on proposed green taxes on fuels, the Yellow Vests sense they can achieve more.
The group is named after the high visibility jackets that all motorists have to carry in France and originally called for a reduction in the price of diesel and petrol.
Now disgruntled groups from Left and Right, including students and emergency workers, have joined their campaign.
This has ensured that Mr Macron’s approval rating – his lowest since he took office in 2017 – is now just 18 per cent, according to a new YouGov poll.
It was conducted the day before Saturday’s riots, with 1006 people making up a representative sample of the French population quizzed.
The 18 per cent figure represents a drop of three points and the third consecutive decline in three months.
Mr Macron came to power in May 2017 as an independent, pledging to reform the country’s sluggish economy and to introduce ecological measures in line with the Paris Climate Change agreement.
Now disgruntled groups from Left and Right, including students and emergency workers, have joined their campaign.