There are houses that want to impress and houses that want to tell a story. The country house of Cordélia de Castellane, an hour north of Paris in the Oise region, is one of the latter - a place for making memories, not for showing off wealth.

Castellane is no ordinary name in the world of design. Half French, half Greek of aristocratic descent, she has been artistic director of Dior Home and Baby Dior since 2012 and one of the most respected interior designers in Paris. But in this house she didn't want to create something new and lacquered - she wanted to preserve the soul of the place. “I renovated a lot, but I was very careful to keep the soul,” she says.

You see it in every room. Inherited furniture, finds from antique shops, textiles and objects gathered over the years tell the story of a family. Castellane openly admits she doesn't like things that sit “in their place” nor overly tidy interiors. “I don't want the obvious,” she says. And it is precisely that deliberate untidiness that makes the house alive.

The kitchen-dining room is always ready to receive guests. Her signature dish - stuffed aubergine - is served here regularly, and the tables are often moved around according to mood, now in the middle of the garden, now in a room with special lighting. Hospitality with her isn't protocol but comfort: “I don't want to host in a stiff or formal way, that isn't me. Only people who mean something to me come in.”

The bedroom is one of her favourite corners, and its appeal, she says, depends on the light and the season. Every room changes with the seasons - the same angle looks different in July than in November. It is a house that breathes together with the outside world.

But the true heart of the estate is the garden. “That is my laboratory,” Castellane says, because from it she draws inspiration for her work at Dior. She describes it as a blend of two sides - the French, clean and symmetrical, and the English, with a brighter, well-organised disorder. “I like it full of tenderness and poetry.”

Flowers, for her, aren't decoration but a rule. Only seasonal, never artificial. “Nature already gives us enough,” she says. She puts them everywhere - on the tables, in the hallways, in the bathrooms, in the kitchen - most often in special vases or small glasses so everything stays light and airy. The greenhouse in one corner of the estate is another of her favourite spots.

And the link between home and work? Castellane turns the usual logic on its head. It isn't the house that shapes her Dior through her - it's the other way around. “The garden is my laboratory, because I have the same love for flowers that Mr Dior had.” A lesson that holds beyond the world of high fashion too: the place where you live doesn't have to be an exhibition. It can be a laboratory - for life, not for photographs.