Seventeen women who have served as ministers in France say they will no longer be silent about sexual harassment in politics.

All 17 signatories to the declaration are current or former ministers.

Among them is Christine Lagarde, the head of the International Monetary Fund and France's former finance minister.

On Monday, the deputy speaker of the National Assembly, Denis Baupin, resigned over sexual harassment claims, which he denies.

"Like all women who have entered spheres that up until then were exclusively male, we have had to fight against sexism," the declaration, in the Journal de Dimanche newspaper, said.

"It is not for women to have to adapt to these places, but for the behaviour of certain men to change."

Examples of some of the sexual harassment suffered by the women are also given in the article.

Denis Baupin denies the allegations against him. Photo: AFP

It explains that Fleur Pellerin, who was culture minister in Francois Hollande's government from 2014 until this February this year, rarely suffered harassment until she was appointed to office.

After her first appointment in government, she was asked by a male journalist if she was given the job "because you are a beautiful woman".

"They feel entitled to have a laugh and to make unwelcome gestures such as patting a woman on the buttocks," another signatory, former Women's Rights Minister Yvette Roudy, told French news channel La Chaine Info on Sunday.

"Some women aren't so offended but others are very offended and are now speaking out. It's time women talk about it and make it known that they are not being complimented but are effectively being treated as whores."

Denis Baupin groped one female Green Party member and sent explicit messages to others, female former Green Party colleagues said in interviews in French media last week.

France Inter said the women chose to come forward after Baupin gave his support in March to a high-profile campaign criticising violence against women.

One of his accusers, Green Party spokeswoman Sandrine Rousseau, said Baupin had groped her breast in a corridor and tried to kiss her.

His lawyer said Baupin could sue the women who made the allegations.