Well, isn't "following construction rules" basically means "use concrete and established plans"? I hope i am wrong, but sounds like it's just impossible to satisfy regulations while building something from dirt and grass
Build things that use materials that aren't fire hazards and have been engineered to support themselves and the stresses they should survive are the primary imperatives of residential construction. The only reason the house I escaped a 2018 firestorm survived was that it was built to code. And the reason the house I was in in 1989 didn't collapse from a massive earthquake was it was also built to code. DIY lacking principles and conventions of civil engineering aren't cool, they're stupid for playing Russian roulette presuming they "know better". There are plenty of nontraditional housing projects that still follow sensible engineering principles.
Two tribunals at two different levels (additional authorities separate from the mayor) judged that they were wrong.
I would argue that you did not explain the actual situation honestly.
> Well, isn't "following construction rules" basically means "use concrete and established plans"?
It does mean that you need to submit plans beforehand. Concrete is absolutely not a hard requirement in France.
But building in a natural protected zone without a permit is asking for trouble. Maybe a small wooden shed would have been ok.
That they had cleaned up the landfill is rather irrelevant, and in fact it means that the terrain might not have been constructible at all.
Even if their project was interesting, as far as I can tell was destroyed because they didn't follow the established rules and built it illegally. But I might be wrong, feel free to send references for this thing.