This is a good hotel for a prince - one of the largest houses in one of the most beautiful cities in the world.

But the 17th century Hotel Lambert, the heart of Paris is now the subject of a bitter conflict.

The French environmentalists are taking a new owner, a prince of Qatar, to court to try to block its plan to renovate it.

They say it would cause "irreversible damage" to a classified historic monument where Chopin composed some of his music and writer Voltaire lived with his mistress.

But the prince, Sheikh Hamad bin Abdullah al-thani, the brother of the emir of Qatar, stressed that its works to restore the mansion beautiful but decaying Riverside in its former splendor.

From the outside the Hotel Lambert on Ile St. Louis is an imposing and majestic building.

But inside, and you soon see that the years have left their mark. Much of the interior is pretty shabby.

Its former owners, the Rothschild family, sub-divided into apartments in the building.

Portions of the wooden structure is rotten. The architect of the Prince had installed wooden supports to hold it in place.

One of the staircases collapsed. Paintings on the ceiling of Charles Le Brun, whose work also graces the Hall of Mirrors at Versailles, were cracked and discolored.

The prince plans for their restoration by French experts.

And he wants to convert the building into a single residence, demolition of walls put up when it was divided about 50 years ago.

But members of the Paris Historical Association, is mounting a legal challenge to the Prince plan because they say it will change the character of the house.

"What we object very strongly the construction of underground parking, install air conditioning and to the outside wall about 50cm higher, and changes to the facades of the return, supposedly, to the state they were in In the 17th Century, "said Peter Housieaux, head of the association.

But the prince's lawyer, Thierry Tomasi, explains the purpose of conditioning is to preserve the paint and prevent them from cracking again.

And he said that the underground parking, it will be useless to continue the parking of cars in the yard, spoiling the look of the entrance.

M. Tomasi said the prince was surprised by criticism of its plans. He says they were written by the leading French and "approved and accepted by the French Committee for Historical Monuments.

"The prince is a true lover of French art and architecture, especially 17th century, including the Hotel Lambert is a famous example," said Tomasi.

"The object of this project is to preserve the building, to preserve all its elements are historical, cultural and architectural value and restoration of this monument to its former glory."

But some 8,000 people signed a petition against the work circulated by the Paris Historical Association.

And the group has enlisted the support of some local celebrities, including former movie star, Michèle Morgan, who used to live in an apartment in the building.

"We do not object to the fact that the new owner is a foreigner," says Housieaux, President of Paris.

"We are grateful to the Hotel Lambert was acquired by a person who has the means to care for him, but we oppose its renewal plan, because it is too expensive for this building "he said.

"The renovation is not intended to restore the building as it was in the 17th century is an issue to do with what is there, keeping the additions made over the centuries and preservation of the building. "

After buying the house two years ago for a princely sum - say nothing of 60 m euros (£50 m) - the plan now is to spend a fortune on repairing.

Until the litigation is resolved, this Parisian monument with its illustrious past facing an uncertain future.