Paris (AFP) - A new law banning cat-calling and harassment of women on French streets will see men fined on the spot for lecherous and aggressive behaviour, France's women's minister said Monday.

The legislation is being piloted by 34-year-old Marlene Schiappa, a feminist and early supporter of French President Emmanuel Macron who wants to tackle sexist male attitudes in public spaces.

"It's completely necessary because at the moment street harassment is not defined in the law," she told RTL radio on Monday in a major interview to outline the law, which is to be voted next year.

The escalating scandal over Hollywood producer Harvey Weinstein's alleged sexual assaults on a string of actresses has rekindled debate on sexual harassment and predation in France.

The MeToo hashtag encouraging women to share their experiences is among the top 10 trends on French Twitter, and a new one has emerged -- #balancetonporc ("Expose the Pig") -- to report sexual harassment in the workplace.

Asked about the difficulty of drawing a line between harassment and flirtation, Schiappa replied: "We know very well at what point we start feeling intimidated, unsafe or harassed in the street."

She cited examples such as when a man invades a woman's personal space -- "by talking to you 10, 20 centimetres from your face" -- or follows a woman for several blocks, or "asks for your number 17 times."

A cross-party taskforce composed of five MPs has been asked to work with police and magistrates to come up with a definition of harassment that can be enforced by officers on the streets.

"The level of the fine is part of our discussions," Schiappa said, adding that neighbourhood police would act on complaints brought to their attention by women.

"The symbolic value of laws that outlaw street harassment is very great," she said.

The legislation will also include provisions such as lengthening the amount of time women have to lodge sexual assault complaints dating from their childhood and toughening laws on sex with minors.

Raphaelle Remy-Leleu of the feminist organisation Osez le Feminisme (Dare to Be Feminist) told AFP: "I hope that social tolerance will decrease after people become more aware" of sexual harassment.

"But there's a lot of work to be done."