* Activist couple challenges French zoning laws

* Movement to live off-grid, in and with nature

* Landlords let homesteaders use land for free

By Regis Duvignau

CHASTEAUX, France, Jan 31 (Reuters) - In a forested area in central France, a young couple lives off-grid in a wood-and-straw cabin. Their aim is not to hide from the law, but to change it.

Jonathan Attias, 33, and Caroline Perez, 34, are the driving force behind the "Desobeissance fertile" (Fertile Disobedience) movement that links up back-to-nature enthusiasts with landowners willing to let them build dwellings on their land.

Attias and Perez built a cabin on a three-hectare plot shared with them by an older friend. Two other people also live on the site.

"We want to show that it is possible for people to live with and in nature," said Attias, who gives legal and practical advice to people who want to live off-grid in cabins, yurts, tiny houses or other impermanent dwellings.

A year ago, the couple built their "compostable" house with wood, stone, bales of straw and recycled materials like tarpaulins and old doors. When they leave, the house will biodegrade naturally.

But in France, like most of Europe, people are not allowed to build housing in forests or on agricultural land, only in designated housing areas and where they must respect building codes.

Attias wants to change that.

"We will bring our case to the media and we want public debate, we want the law to change," he told Reuters.

His mayor disagrees.

"Everybody wants to change the law when it suits them. What they are doing is forbidden," said Jean-Paul Fronty, mayor of the village of Chasteaux, with 744 inhabitants.

Attias and Perez live in the woods by choice. Two years ago they were urban professionals in Paris. Attias still teaches at a Paris university two days a month and works as a freelance journalist. Perez is a doula who assists with childbirth.

They own a car, they have medical insurance and their four-year-old daughter goes to school in the village, a three kilometre walk from their cabin, which is heated with a cast-iron wood stove and powered by a solar panel.

Both vegetarians, they tend a big vegetable garden, but also get free unsold produce from a bio-store in the village. Water comes from a spring and is made safe with carbon filters.

"We are the guardians of the forest. We don't degrade our environment, we upgrade it," he said. (Reporting by Regis Duvignau and Geert De Clercq; Writing by Geert De Clercq; editing by Mike Collett-White)

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