French President Emmanuel Macron on Monday took to Tik Tok and Instagram to try counter misinformation about vaccines following a third weekend of demonstrations over a controversial Covid health pass.

Macron discarded his customary dark suit and tie for a black t-shirt in a short video from the presidency's holiday residence in southern France, in which he repeated that vaccines were the "only weapon" that could beat back a fourth wave of coronavirus.

"Some of you have been hearing false rumours, some of it rubbish it has to be said," he said in the selfie video, in which he urged the vaccine-shy to put their questions and concerns directly to him.

He was speaking after an estimated 200,000 people demonstrated across France on Saturday.

The protests were the biggest since Macron last month announced that people would have to furnish proof of vaccination, a negative Covid test or recent recovery from Covid to gain entry to most museums, cinemas and sports venues.

The rules will be extended to bars, restaurants, long-distance trains and shopping centres on August 9.

Opponents accuse Macron of running a health "dictatorship", saying the measures impinge on freedom of choice.

In scenes reminiscent of the "yellow vest" anti-government protests of 2018-2019, tens of thousands have staged protests, some of which have ended in rioting. 

Macron, who is expected to seek re-election next year, has been the chief target of the demonstrators' ire.

On Saturday night, a vaccine centre on the French Caribbean island of Martinique was set alight, while in the southern city of Montpellier demonstrators rounded on a pharmacist conducting Covid tests, accusing him of being a "murderer" and a "traitor".

So far, 42.6 million people in France have received at least one vaccine shot, representing 63.2 percent of the population. Of these, 35.7 million are fully vaccinated.

A further 19,600 infections were recorded on Sunday, up from under 5,000 in mid-June  -- an increase blamed largely on the spread of the Delta variant.

The government's Covid advisory committee president Alain Fischer said Monday he believed  the 90-percent vaccine coverage among over-12s needed for herd immunity could be achieved by "the start of the autumm".

Nearly 112,000 people have died in France since the start of the pandemic.