From Rodin and Courbet's naked muses and lovers to Degas's clinical study of the female form, the nude has always taken pride of place in French art.

But Paris is now being accused of showing such philistine ingratitude to its life models that scores went on strike yesterday, taking to the streets to pose naked in freezing temperatures to shame the state.

In front of the tastefully decorated Christmas trees outside Paris city hall's culture department, the naked and goose-pimpled models demanded a pay increase, proper contracts and, most of all, respect for their craft as they held trade union banners in the pose of Delacroix's Liberty Leading the People.

The disrespect shown to the models was "proof that something is badly wrong with French society", shouted one shivering male model through a megaphone. Artists, students and art teachers sat sketching them in support.

The row began when Paris city hall, which runs an array of life-drawing classes, banned the tradition of the "cornet", a piece of art paper rolled into a cone and passed round for tips as a model gets dressed after class. Surviving on the minimum wage with no fixed contracts, holiday pay, security cover or job security, the crash-strapped models said the tips allowed them to survive.

They also wanted to quash the misconception that life-modelling was merely something students and retired people did for pocket money. Sean Connery may have posed naked in Edinburgh to make ends meet when he was a struggling actor and Quentin Crisp may have spent the war years posing naked at Derby School of Art, but in France life-modelling is widely seen as a serious career choice.

"This is a craft that should be respected, not just anyone can take their clothes off and hold a pose," said Deborah, 28, one of the strike organisers, who has worked as a full-time life model for four years. "It is artistic and physically demanding work."

She had to swim regularly to stay fit enough to hold poses and felt models should be given access to subsidised municipal sports facilities to keep in shape for their jobs, as well as access to museums to do research for their poses.

Leela, 33, a singing teacher and part-time model, said the "cornet" was crucial to supplement her pay of €10 an hour.

"Everyone puts in one or two euros, which can add up to €20 to €30. The next day I can go to the market and fill my fridge."

Gerard Vilage, an art teacher from Paris's Beaux Arts Ateliers, said: "How can we teach drawing without these people, if they are left with meagre pay and no protection?"

Christophe Girard, Paris city hall's culture supremo, who also moonlighted as a life model in his student days, tried to calm the row, urging the ministry of culture to review life models' status. He said: "Regarding tips, we can't let people collect money that's not taxed while working in a state building.

"But I think this was a lovely protest in the French, gaulois spirit of resistance - taking your clothes off outside 10 days before Christmas shows real conviction.

"Life modelling is an activity that is fragile and possibly under threat and I don't want to see it disappear."

Case study: Christophe Lemée, 52

After 30 years as an actor, I began life modelling to support my own theatre projects. It's a beautiful craft and very physically demanding. You have to forget yourself and move beyond the contours of your own body. It's not my body the artists are trying to capture, but the essence of human nature, existence and all the mystery that goes with it.

I will often do nine-hour days - you have to be very athletic to do that. Each session is three hours long, divided into 45 minute poses followed by 15 minutes' rest. It's no easier holding a sitting pose than a standing pose. The weight will always be concentrated on some part of your body. I call it dancing without moving. You need a lot of psychological concentration to cope. You have to learn what your body can and can't do. I try to swim for an hour in the mornings to keep my body in condition for the poses.

You are naked and defenceless in front of a room full of people, but it's not the same brash nudity you see everywhere in modern society. It's more spiritual. I'm exposed but I know that the people looking at me are exactly the same as me under their clothes.

Life-modelling has always been crucial for western art, which is all about the glorification of the human body.

You have a profound artistic relationship with the people who draw you and that is very rewarding.