A model charter backstage at Christian Dior.

In fashion history books, 2017 may well go down as the year in which models found their voice — and the industry started listening more intently.

For the first time, beginning with the spring season, French luxury groups Kering and LVMH Moët Hennessy Louis Vuitton implemented strict new measures governing the well-being of models, resulting in a ban on size-zero and under-16 models from shows including Gucci, Louis Vuitton, Saint Laurent, Givenchy, Balenciaga and Céline.

Backed by François-Henri Pinault, chairman and chief executive officer of Kering, and Antoine Arnault, ceo of Berluti and a director at LVMH, the charter on the well-being of models unveiled in early September has had a ripple effect on other houses, and not just in Paris.

Among its directives: Models were to provide a medical certificate less than six months old certifying their overall health; models under 18 were to be accompanied by a chaperone or guardian at all times, and brands were to provide return transport for any model working after 8 p.m.

For casting director James Scully, who set the ball rolling during Paris Fashion Week in February by publicly denouncing several brands for allegedly mistreating models, the change has been swift and dramatic.

“So far, I think it’s been incredibly positive,” he said. “I can’t thank Kering and LVMH enough because they were really, really, really serious about getting this under way.”

Officials at Kering and LVMH said there was no going back.

“In a way, it has lit a spark, and for me, there is a before and an after,” said Marie-Claire Daveu, chief sustainability officer and head of international institutional affairs at Kering.

Marc-Antoine Jamet, secretary-general of LVMH, said he hoped other groups would publicly endorse the charter. “We want to be at the heart of a movement and to bring everyone together,” he said.

Scully said models who speak out are brave — and are finding an increasingly supportive community online.

“You’re probably going to get called out, and that is the thing I think in the last year that has changed completely,” he said. “I’m wondering in this next year how much this will or won’t go away. My feeling is that these things won’t go away anymore, because once you open the door, that’s it.”