France’s feminist organisations have raised the stakes in their bid for equal pay, calling for French women to walk off the job on Monday to protest against earning less than male colleagues.

Following in the footsteps of Icelandic women a month ago, women were asked to go on strike at precisely 4:34pm and seven seconds — the theoretical moment when French women in effect start working for free until the end of the year because of the average pay gap to the country’s men.

The call for a work stoppage in France by groups including Les Glorieuses, Les Effrontées and Osez le Féminisme drew attention to an enduring inequalities in pay. French female workers earn on average between 15 and 20 per cent less than men, according to a range of estimates by Eurostat and Insee, the French statistical institute.

Eurostat and Insee figures also show that French women still earn about 9 per cent less than their male counterparts when they are in the same job, with equivalent responsibilities and working hours.

The French groups behind the strike were following the example of women in Iceland a month ago when thousands of female workers walked out of their workplaces in a similar gesture.

With France heading towards presidential elections next year, politicians were among those offering support. ‘I want a France that respects gender equality,” tweeted Alain Juppé, one of the leading rightwing presidential candidates. Manuel Valls, the prime minister, tweeted: “Gender equality should be at the heart of the Republic.” Najat Valaud-Belkacem, education minister, said it needed to be “a fight of the entire society”.

Amid rain and biting cold, however, the crowd that rallied in Paris on Monday was a far cry from the hundreds of thousands of protesters who took to the streets this year to protest against the Socialist government’s labour reforms.

Several hundred protesters demonstrated on Monday in the Place de la République, using slogans such as: “If you like working for free, clap your hands,” or “All work deserves payment.”

The protest drew attention to the level of inequality in France. Whereas Iceland ranks first among 144 countries in the Global Gender Gap Index of countries getting closest to gender equality, France — ranks 17, behind Germany, the Netherlands, Slovenia or Namibia.

The pay gap is “only the tip of the iceberg”, Osez le Feminisme said on Monday, pointing that nearly eight in ten temporary workers were female.

A 2011 law requires companies in the blue-chip CAC 40 index to reach a level next year where 40 per cent of board members are women, compared with about 35 per cent at present. There is only one French female chief executive of a CAC 40 company: Isabelle Kocher, CEO of Engie, the utility company.

On Monday, French women and men also used social media to raise awareness, using the #7novembre16H34 hashtag.

Dry humour was rife too: “It’s good that women stop working at 4:34pm,” the tongue-in-cheek @Nain_Portekoi tweeted. “It leaves them time to do the cleaning, the dishes, and to take care of the children.”