Executives at fashion houses and talent agencies that use excessively thin models in France could face six months in prison and a fine of 75,000 euros [$82,000].
French lawmakers approved the measure Friday, a day after voting to outlaw websites that encourage readers to get thin by starving themselves.
Anyone whose body mass index falls below levels proposed by health authorities is forbidden from working as a model, according to the amendment to the French health bill.
More than 200,000 people suffer from anorexia in France - five times the government's estimate - according to Association Autrement, a nonprofit organization that seeks to help those afflicted by eating disorders.
Anorexic French model Isabelle Caro brought the issue to the fore in 2007 when she posed nude for an advertising campaign to raise awareness about the illness.
She died in 2010.
Thursday's vote means owners of websites that promote harmful and potentially fatal dietary restrictions could face a year in prison and a fine of 10,000 euros.
The amendments are part of Socialist President Francois Hollande's health bill that will also need to be approved by the Senate before becoming law.
France is home to some of the world's best-known fashion companies, including Chanel, Dior and Saint Laurent.