French lawmakers backed a bill late Monday setting the minimum age of sexual consent at 15, marking a major step in a country with traditionally permissive attitudes about sex.

Members of the lower house of parliament voted unanimously to bring France's consent laws in line with most other Western countries, following a wave of allegations of sexual abuse and incest described as France's second #MeToo movement.

Under the bill, sex with children under 15 would be considered rape, punishable by up to 20 years in prison, unless there is a small age gap between the two partners.

Justice Minister Eric Dupond-Moretti said the vote sent a clear message: "Children are off-limits".

Under current French law, prosecutors had to prove that a minor was forced, threatened or tricked into having sex with an adult in order to bring charges of rape or sexual assault.

The draft law was initiated by members of the Senate, who had suggested the age of consent be set at 13, which would have been one of the lowest in Europe. 

But President Emmanuel Macron's government pushed for it to be set higher.

The bill does allow for sex between a teen and a young adult up to five years older -- a gap criticised by some MPs as too large but which Dupond-Moretti defended, saying he did not want "to put a youngster aged 18 on trial because he had consensual sex with a girl aged fourteen and a half."

The bill, which was the subject of some 300 amendments in the lower house National Assembly, now returns to the Senate for a final vote.

The legislation also cracks down on online paedophilia, with any person caught trying to groom children aged under 15 for sexual acts over the internet facing up to 10 years in prison and a fine of 150,000 euros ($180,000).

The issue of consent has repeatedly come up for debate since 2018 when it emerged that a 28-year-old man, who had sex with an 11-year-old girl he met in a park, had initially been charged with a lesser sexual offence, not rape.

The case caused a public outcry in France, where sex between adults and minors has previously often been shrugged off as harmless in cases where the encounter was presented as consensual, usually by the adult.

The country's top appeals court is this week set to rule on another case involving allegations of child abuse.

The case was brought by a woman, named as "Julie" in press reports, who claims she was raped by over 20 firefighters when she was aged 13-15 and was repeatedly hospitalised for severe anxiety attacks.

In France, the ambulance service is staffed by firefighters. 

The accused claimed she consented to sex, which she denies.