RENNES, FRANCE (AFP) - Dozens of restaurants in the western French region of Brittany have vowed to defy controversial new rules requiring them to check whether diners have been vaccinated, tested negative for Covid-19 or recovered from the virus before serving them.

From Aug 9 on, people will need to produce a Covid-19 health pass in order to eat out or have a drink in a bar in France, as well as take a long-distance train or domestic flight.

The new rule, which brought over 200,000 protesters onto the streets last weekend, is already in effect in entertainment and sporting venues with more than 50 people.

Restaurant owners have fiercely resisted the measure, warning it will drive customers away.

"We refuse to play the role of health police by checking, sorting and turning customers away from our premises," a group of 44 cafe and restaurant owners in Brittany, a region popular with tourists, wrote in an open letter on Facebook on Tuesday (Aug 3).

The owners of the hostelries spread over 38 towns and villages added that a "red line had been crossed" in terms of personal freedoms and that welcoming all patrons without distinction was part of their "core values."

President Emmanuel Macron's government has defended the new rules as necessary to tamp down a fourth wave of infections driven by the Delta variant and ward off a possible fourth nationwide lockdown.

So far 42.8 million people have received at least one vaccine dose, representing around 64 per cent of the population.

The government's Covid advisory committee says 90 per cent of French people over 12 need to be fully vaccinated in order to achieve herd immunity.