London's Metropolitan Police said two officers were assaulted as they attempted to control angry right-wing demonstrators marching through Whitehall and Piccadilly.
The officers were taken to hospital where they received treatment for their injuries.
Video posted on social media appeared to show some of the activists in hi-vis jackets clashing with officers. One clip showed a man being handcuffed and led away.
A Scotland Yard spokesman said: “Six arrests were made following a moving yellow vest protest in Whitehall and Piccadilly on Saturday, 16 February. Two officers were assaulted during the course of policing the protest."
They added: “Both officers were taken to hospital for treatment of their ABH and common assault injuries. Neither had to remain in hospital following treatment received.
“Four people were arrested on suspicion of public order related matters, with a further two arrested on suspicion of assault on police. All those arrested were taken to police stations for questioning.”
Yelling vest demo just kicked off in Haymarket. Big time! pic.twitter.com/RLWCB8oPBD
— Ali. 🐳🐺 (@ali__samson)
In recent weeks pro-Brexit campaigners have begun wearing the high-vis vests made famous by French anti-fuel tax protesters at small rallies and marches across the UK.
Regular demonstrations have spread to cities including London, Manchester and Sheffield on Saturdays.
The 29-year-old was charged with assault and a public order offence, and has been bailed to appear at Manchester and Salford Magistrates’ Court next week.
He claims the yellow vests are not violent, but he has told police that he will “give them a war” in scuffles at protests.
Meanwhile in France on Saturday, police fired tear gas to disperse protesters who threw projectiles and set bins on fire in Paris, Lyon and Bordeaux during the 14th straight weekend of yellow vest protests.
In Rouen in the north, four people were injured after a driver tried to force his way through a crowd of protesters.
The number of street protesters in France have fallen from highs of over 300,000 nationwide in November to over 51,000 last week, according to government estimates.
A poll earlier this week showed dwindling support for the yellow vest movement in France.