The French government has insisted it will not seek to ban Muslim women who wear headscarves from volunteering to help on school trips after outrage when mothers accompanying pupils were told to remove theirs.

One mother said pupils were distressed and traumatised when a far-right politician told her to take off her headscarf in a regional parliament in eastern France, where she was helping out on a primary school outing for her son’s class.

The incident has reignited a long-running row over French secularism and whether politicians can decide how Muslim mothers should dress when volunteering to take part in school activities.

There is no law banning mothers in headscarves from accompanying school trips; indeed, France’s state council ruled in 2013 that mothers were free to wear whatever they wanted on outings.

However, there is growing pressure from the right in France for a ban on mothers in headscarves taking part in school activities. Some argue French law already bans girls from wearing headscarves inside state schools and mothers should be made to comply with the same strict neutrality rules imposed on French state workers, such as teachers, who cannot wear religious symbols in the classroom.

One mother, identified only as Fatima E, spoke out about her experience of being told to remove her veil in the Bourgogne-Franche-Comté regional parliament building by Julien Odoul from Marine Le Pen’s far-right National Rally party.

A fierce row had broken out in the chamber when the regional parliament speaker, the Socialist Marie-Guite Dufay, replied to Odoul, saying that neither French law nor the rules of the chamber banned a member of the public wearing a headscarf.

Fatima, who was pictured comforting her distressed 10-year-old son in the public gallery, told the Collective Against Islamophobia in France: “I felt rejected in a way I never had been before.”

She was a regular volunteer on school outings, and her son’s teacher had asked her to come on the trip. “I heard someone say ‘in the name of secularism’ and I heard people start shouting and getting angry,” she said.

“The only thing I saw was the children’s distress. They were really shocked and traumatised … They kept turning round to me, saying, ‘But it’s [directed] at you! Is it you they’re telling to take off your headscarf?’”

She said of the politicians who told her to uncover her head: “They have destroyed all the work I was doing indirectly with this class, where children of immigrant roots often had an attitude of thinking France was against them.”

In a separate incident, a nursery school visit to a fire station in Creil, north of Paris, failed to go ahead on Monday when a firefighter told a mother accompanying the trip that she had to remove her headscarf. The fire service later said it was a mistake and the officer apologised.

The French prime minister, Édouard Philippe, told parliament mothers were free to dress as they pleased and there was no need for new legislation on what should be worn on school trips. He said he would fight “to defend secularism”, which meant protecting people’s religious freedoms.

But there are divisions within Emmanuel Macron’s centrist La République En Marche party.

The education minister, Jean-Michel Blanquer, said last month he would rather avoid having mothers in hijab as volunteers on school outings. He said although he accepted mothers could legally wear what they pleased, “the headscarf itself is not desirable” because of “what it says about the status of women, what it says about our values”.

When one spokeswoman from Macron’s party said she would support a rightwing proposal to ban mothers in headscarves attending school trips, others within the party replied with a #NotInMyName campaign against any ban.

A senate committee is seeking to discuss potential legislation on mothers’ dress codes later this month.

This week, 90 personalities, including actors and writers, signed an open letter in Le Monde calling for Macron to publicly condemn the request for the mother asked to remove her headscarf in the regional parliament.

They called for Macron “to say with force that Muslim women, whether they wear a headscarf or not, and Muslims in general have a place in our society – and to refuse our fellow Muslim citizens being monitored, stigmatised or denounced for the practice of their religion”.