They no longer know Paris who only Paris know. To see fine buildings made from the warm, elusive, cream-grey stone of the French capital, you once went to the Louvre, or to the Invalides or to the Place de la Concorde. Now, to contemplate the glories of "Paris stone", you can also visit Los Angeles or Las Vegas, Kuwait, Knightsbridge or Marlow in Buckinghamshire.
The stone which illuminates the "city of light" is rolling around the world.
"Paris stone", which actually comes from a half-dozen limestone quarries in the Oise, 25 miles north of Paris, has become an architectural fashion accessory for the wealthy and famous. Its cheaper varieties are also much in demand in Britain, where they compete success-fully with local stone as a versatile, and economical, building material.
Michael Jordan, the retired basketball superstar is the latest celebrity to refit his mansion in Los Angeles with so-called Paris stone. The Paris-born founder of the online auction company eBay, Pierre Omidyar, has clad a whole mansion with Oise stone, in the Nevada desert near Las Vegas.
The University of Stanford in California is constructing several new buildings which will be covered with one of the finest grades of Lutetian limestone, hacked from the earth 5,600 miles away at Saint-Maximin, near Chantilly in the Oise.
From a series of big holes around this village came the stone which fashioned most grand Paris buildings from the 17th century onwards, including parts of the Louvre, the Place de la Concorde and Les Invalides. There are some exceptions, such as the monumental blocks for the Arc de Triomphe, which came from near Beaune in Burgundy, 200 miles to the south.
However, the quarries of Saint-Maximin can authentically claim to be the birthplace of the largely stone-built Paris that we know today. The southern Oise provided 90 per cent of the stone for the Haussmann era (post-1860) avenues and streets which give the French capital its sweeping and uniform style (and its elusive colouring, ranging from shining white to nicotine yellow).
For decades stone went out of fashion as a building material, partly because of the concrete revolution inspired by the Swiss-French architect Le Corbusier (who wanted to knock down a large part of Paris).
In the past decade, stone – and especially Paris stone – has come triumphantly back into style. Giorgio Armani helped to encourage the trend by using one of the most expensive varieties of Oise stone for the internal floors and walls of his shops around the globe.
Quarry operators in Saint-Maximim say that several Hollywood film stars have ordered shiploads of Paris stone for building projects in greater Los Angeles in recent years. They decline to give their names for reasons of business confidentiality. Several prestigious new buildings in London have used Paris limestone, including Trevor House, an office block opposite Harrods on the Brompton Road. None of these buildings copy Parisian architecture. They use Paris stone because of its decorative and building qualities and its relative, perhaps surprising, affordability.
A "Tellytubby" style mansion built recently into a hillside near Marlow in the Thames Valley uses flag-stones from Saint- Maximin for its grand entrance hall. (This can be lowered and flooded to create an indoor swimming pool – something neither the Louvre nor the Tellytubby house have ever had.)
To solidify its sudden celebrity, the southern Oise, around Saint-Maximin and Chantilly, has applied to the French state to become the first place to be granted a building stone Appellation Contrôlée – a badge of official regional excellence – like that given to a wine or a cheese. The southern Oise is also developing a tourist heritage trail to encourage visitors to explore the rich history of the ancient, underground quarries in the area, some of which date back to Roman times.
Stéphane Pavlovic, director of the Rocamat quarry near Saint-Maximin, the largest in the area, said:"I have been manager of this quarry for three years and in that time our foreign orders have increased five-fold.
"Of course, the fact that this is the stone which built Paris is one of our main selling points. But it is also a very, very fine building stone, which can come in an extraordinary range of colours and qualities."
One old rock face in the Rocamat quarry looks like the wall of a medieval cathedral, made from a single vast piece of butter-coloured rock. Elsewhere, the quarry resembles a giant child's building set, littered with blocks of limestone as large as cars or trucks.
All are marked with fluorescent letters indicating their future uses. These range from the restoration of Paris monuments to new buildings at Santa Clara and Stanford universities in California.
And what were the large blocks marked with a fluorescent red "K" for?
"Ah, that's a very interesting order," said Olivier Dulac, the Rocamat sales manager. "That stone has been ordered for a very large, private mansion in Kuwait. It will be in the shape of a pyramid, with more than 1,000 square meters of living space."
The stone – 600 cubic metres in all, worth around €300,000 (£210,000) – will be shipped to Italy. There it will be given precisely the "rough" designer-look desired by the wealthy Kuwaiti client and sent on to the Gulf.
Up until the 17th century, Paris was constructed mostly from stone excavated through tunnelling underground just outside the city itself. As the city spread over the old quarry- workings, the tunnels began to collapse. The old quarries were later strengthened and turned into the catacombs, which survive under large parts of Paris to this day.
In the second part of the 17th century, Louis XIV's chief minister, Jean-Baptiste Colbert, created a commission to decide which stone would best replace the local building material. The commission identified the stone from the southern part of the Oise – conveniently linked to Paris by river – as an almost perfect match for the city's existing monuments, such as the Cathédrale de Notre Dame.
Mélanie Baticle, of the Maison de la Pierre in Saint-Maximin, an organisation set up to promote "stone" tourism and knowledge of stone history in the southern Oise said: "The principal grades of Oise building stone are, when extracted, soft and easy to cut and shape. At the same time – paradoxically – they are very resistant to weathering and time.
"Exposure to the air gives them a kind of resistant coating. That made them perfect for building in Roman times and in the 17th century and has made them much sought after again today."
Between the 17th and 19th centuries, the stone was extracted by tunnelling through hill-sides deep into the earth. In the 20th century, open-cast quarries were developed which came across thinner layers of harder limestone closer to the surface. This tougher stone has become greatly valued – and valuable – because it can be sliced by machine into thin, flat sections to cover walls and floors. All the varieties of Oise sandstone – up to 12 different grades – come in a subtle range of colours, which explain the different hues within a single street in the French capital.
"Just like with the finest wines, the stone you quarry from one spot can be completely different from the stone 100 metres away," M. Pavlovic said. "Here, in this quarry, we are spoiled. We have three, four, five different kinds of stone – all with their different colours and uses and values – piled up in the ground on top of one another."
The harder, sliceable limestone sells for around €2,000 a cubic metre. The different grades of softer building stone sell for between €550 and €150 a cubic metre, which is very competitive with other building stone all around the world.
But how can it be commercially viable to send something as bulky and heavy as stone to the ends of the earth?
"It's not really a problem," said M. Dulac. "Shipping costs are not enormously high, compared to the value of the stone. So, even in California, say, we can sell Saint-Maximin stone for only about 15 per cent more than you would pay in France.
"To send stone to Britain is obviously even cheaper. You have very fine building stone in Britain too but it is becoming rare and also expensive to exploit. Britain is becoming a very big market for us."
Limestone from Burgundy and Caen in Normandy also sells well in Britain and across the globe. For Caen stone, travel is nothing new. Its qualities were well known to the Norman conquerors of Britain. Canterbury Cathedral, Westminster Abbey and the Tower of London were partially built from Caen stone.
Fréderic Milleville, is manager of the smaller Ouachée et Corpechot quarry on the edge of Saint-Maximin. It was this quarry which supplied the stone for Michael Jordan's Los Angeles mansion, Pierre Omidyar's Nevada château and the Tellytubby house in Marlow.
When the eBay founder came, with his family, to choose his stone, the Ouachee quarry set out different lumps of rock like contestants in a beauty contest.
M. Milleville said: "What he wanted most was a kind of rock which would not shine too harshly in the Nevada sunshine."
Shipping enough Paris stone to Nevada to build a mansion was not a problem, according to the Ouachée et Corpechot quarry manager.
M. Milleville said: "Shipping companies actually welcome very heavy cargoes like stone. If they have heavy containers at the bottom of the hold to ballast the ship, they can safely use up all the available space above with lighter containers. That means we can bargain on shipping rates."
The whole of the Ile de France, the region around Paris, is built on foundations of limestone laid down 45 million years ago. At that time northern France was covered by a shallow sea. For five million years, the waters laid down successive layers of sedimentation composed of sand, sea-weed shellfish and microscopic organisms. During the millennia, the layers have metamorphosed into different grades of limestone. Some are excellent for buildings; others are crumbly and useless.
In some of the prized upper layers at Saint-Maximin, you can still pick out thousands of tiny "coquillages" – traces or fossils of shell-fish – in each block of stone. This type of stone used to be discarded for its irregularity but it is now prized for its texture and beauty.
The Saint-Maximin area is honeycombed with old stone workings. One of them, the Carriére de la Pelouse, starts near the spectacular Château de Chantilly and extends far under the Chantilly race-course.
Mme Baticle and the curator of the Institut de France-owned château, Nicole Garnier, took The Independent on a tour of the labyrinth of man-made tunnels and caverns, which date back to the early 18th century.
The Institut intends to open the caverns to the public once a month, as part of the drive to increase interest in the stone heritage of the southern Oise.
These old subterranean stone workings once found a use as mushroom farms, the origin of the celebrated "champignons de Paris". Almost all of the mushroom farms have now been wiped out by competition from eastern Europe.
For the quarrymen of the Oise, times have never been better. They can barely keep up with demand. The only potential problem is that it takes 40 million years to create new Paris stone.
M. Pavlovic, director of the Rocamat quarry, said: "At the present rate of extraction, we have 20 or 30 years' supply of the harder, more expensive stone and a century or more of the building stone."
He cast his eyes enviously on the trees at the quarry's edge. "We have another two or three hectares there that we can dig into. Beyond that you are into the grounds of the Château de Chantilly. And there, unfortunately, quarrying is forbidden."