France's lower house of parliament has voted to toughen laws on the rape of minors but stopped short of setting a legal age of sexual consent.

During a heated debate ending early Wednesday, lawmakers decided against creating what would have been France's first law on a legal age below which a minor cannot agree to a sexual relationship with an adult — the proposal was 15.

Instead, they approved a clause in which relations between an adult and a minor under 15 could be classified as rape if "the victim lacks the ability to consent". In other cases, it would be classified a "sexual assault."

But rights groups — who pushed for a firm age limit — have reacted angrily.

The law now goes to the Senate for approval.