Ultra-thin models will be banned in France and fashion houses and agents will be subjected to fines and possibly jail under a new law approved by the country's MPs.
Workers will need to show they have a body mass index (BMI) of at least 18 by presenting a medical certificate if they wish to compete as a catwalk model.
Agents who employ models who are considered too thin could face up to six months in prison as well as a €75,000 (£55,000) fine. Socialist MP, Olivier Veran led the amendment.
"The activity of model is banned for any person whose body mass index (BMI) is lower than levels proposed by health authorities and decreed by the ministers of health and labour," the bill said.
"The prospect of such a punishment will have the effect of regulating the entire sector," said Veran.
In another move to target unhealthy weight loss, the lower house of parliament passed a separate law making it illegal to condone anorexia.
Around 40,000 people suffer from the condition in France with women and girls comprising a significant proportion – nine out of ten – of people suffering from anorexia.
In 2007, 28-year-old former French fashion model, Isabelle Caro died after posing for a photographic campaign to raise awareness about anorexia. At the time of her death, she reportedly weighed a mere 4st 8lb (68lbs).
Her mother, Marie Caro later committed suicide after being consumed with "enormous guilt" at the death of her daughter.