More than 80,000 police officers are mobilising across France for the ninth weekend of gilets jaunes anti-government protests as Emmanuel Macron prepares to launch a three-month public debate process that he had hoped would channel protesters’ anger away from the streets.

Demonstrators were expected in Paris on Saturday where the government fears a repeat of last weekend’s violent skirmishes with police. More than 5,000 police will be stationed in the capital and all local officers have been called back from leave.

There could also be large protests in the small town of Bourges in central France after gilets jaunes groups online suggested its central location made it easy to reach and that it had less of a police presence.

The town of 66,000 people – fearing clashes and violence – has closed museums, cleared building sites, removed parking meters and covered up electronic signs at bus stops. The local police chief on Friday banned any demonstration in Bourges historic centre, meaning protestors would have to keep to boulevards on the edge of the town.

Many shop owners in the town said they could not afford to shut their businesses on the first Saturday of the January sales and would stay open until the last minute, closing only if there was a security risk – but fearing the majority of customers would stay away.

Gilets jaunes demonstrators have continued to barricade roundabouts across France. The government said about 60% of speed cameras across France had been damaged or destroyed since the start of the protest movement in November. Officials said the speed cameras that do remain in use had shown more drivers breaking speed limits, presumably thinking they would not be caught.

Although the gilets jaunes protests – named after the yellow hi-vis jackets worn by demonstrators – began in November as a revolt against fuel tax, local politicians said fury over this summer’s move to cut speeds to 80km per hour (50mph) on many secondary roads had played an important roll in mobilising protests in the countryside.

“People are still complaining about it in the regions,” Christophe Jerretie, an MP for Macron’s La République En Marche party in Corrèze, said of the speed limits. Some protesters want the speed limit changes scrapped but the government believes the measure, which will be evaluated fully next year, has already saved hundreds of lives.

The nationwide “great national debate”, which the president suggested in December as a solution to gilets jaunes’ complaints that citizens do not have enough say in policy, will launch on Tuesday. But it would be an unprecedented exercise that has proved complex to organise.

The head of France’s national debates commission, Chantal Jouanno, withdrew her participation in Macron’s debate this week amid outrage over her €14,666 monthly salary, leaving the government scrabbling to reorganise proceedings.

Questions remained over whether the debate process would be focused on town-hall meetings and whether the government would take into account what was said.

The topics to be discussed included the tax system, reform of state institutions as well as democracy and citizenship. Fears have been raised that groups such as the powerful lobby against same-sex marriage would use the debate to reopen discussion on society issues. But the government said topics such as same-sex marriage, which came into force in France in 2013 amid massive street protests, would not be up for discussion.

“It’s out of the question to roll back on abortion, the death penalty or equal marriage,” the government spokesman Benjamin Griveaux said.

Macron and his party want to hark back to the big door-to-door consultation on the nation’s problems that he set up before his presidential bid in 2017. But an Odoxa poll found seven out of 10 French people did not think the debate, which begins next week, would be useful for the country.

In the meantime, the government has focused on law and order measures in response to violence at gilets jaunes protests as a way to try to win back support for the centrist, pro-business Macron, particularly among voters on the centre-right.

The prime minister has promised new laws, including setting up a register of rioters, similar to that used to deter football hooligans, to force them to report to police and prevent them from joining demonstrations.

Human rights lawyers have said some of the proposals could go against the French constitutional right to protest. But the government has been convinced that showing “authority” was crucial to win support back to Macron before European elections.

Two recent polls have shown approval ratings for Macron and the prime minister rising again after a period of decline – although approval ratings for the president remained beneath the symbolically low level of 30%.

A counter protest against the gilets jaunes demonstrators has been scheduled for 27 January in Paris.

Annual Cevipof polling released in Le Figaro on Friday showed what the political scientist Bruno Cautrès called the highest level of “mistrust and anger” at French politicians and state institutions in 10 years of polling.