France has introduced penalties for agencies that use dangerously thin models.
Those found guilty could be fined €75,000 - or spend 6 months in jail.
The law was passed in Paris yesterday to try and combat anorexia in the industry.
The legislation, as reported by Reuters, says, "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 labor."
Reuters also reports that the lawmaker behind the bill has said that models will have to present a medical cert showing a BMI of at least 18 - for example a weight of around 8.6 stone for a height of 5.7 feet.
Another measure, aimed at combating anorexia, suggests website operators offering advice to readers 'encouraging eating restrictions for a prolonged period of time, resulting in risk of mortality or damage to health' could face jail time or fines of up to €100,000.
Body image expert Natasha Devon thinks the new legislation could be hard to enforce:
