The French parliament has voted to ban ultra-thin catwalk models, despite protests from modelling agencies in the world’s fashion capital.

Anyone whose body mass index is below a certain level will not be able to work as a catwalk model, according to the amendment voted in by the national assembly.

Agencies found to employ models considered too thin could face a fine of up to €75,000 (£55,000) and six months in prison. The measure is part of a wider crackdown on anorexia backed by President François Hollande’s government.

“The prospect of such a punishment will have the effect of regulating the entire sector,” said Olivier Veran, the deputy proposing the amendment, who said similar measures had been taken in Spain, Italy and Israel.

The health minister, Marisol Touraine, previously said young models should “eat well and look after their health”. She added: “This is an important message to young women who see these models as an aesthetic example.”

However, the National Union of Modelling Agencies has complained this would affect the competitiveness of French modelling.

The law comes after a similar amendment was passed under which people found guilty of inciting others to “extreme thinness” could face a year in prison and a €10,000 fine. That law was aimed at so-called “pro-ana” websites that some accuse of encouraging anorexia.

An estimated 40,000 people suffer from anorexia in France, nine out of 10 of them women, according the health ministry.