AFP - A French court on Tuesday blocked a decision to allow a Qatari prince to modernise a pristine 17th-century mansion, one of the gems of historic Paris, a lawyer for a residents' group said.
   
Locals went to court to block the work by Prince Abdullah Bin Abdullah Al-Thani, brother of Qatar's emir, who bought the Hotel Lambert on the Ile Saint Louis, an island on the River Seine and a UNESCO heritage site, in 2007.
   
The judge agreed to suspend the permit given to the prince in June by the culture ministry to turn the delapidated mansion into a family residence, said Michel Huet, lawyer for the Paris Historique association fighting the plans.
   
Built in the 1640s at the eastern tip of the island, not far from Notre Dame Cathedral, the Hotel Lambert was designed for a rich financier by the architect Louis Vau, who went on to oversee a major expansion of the Chateau de Versailles for Louis XIV.
   
Rich with history, the mansion's uses over the years ranged from a hideaway for the 18th-century philosopher Voltaire and his lover, to a political headquarters for Polish exiles in the following century.
   
Prince Abdullah acquired the hotel from the Rothschild banking family for some 60 million euros (86 million dollars) in 2007, and with his son Hamad Bin Abdullah Al-Thani commissioned French architects to restore and convert it.
   
His plans for the building were watered down after months of talks between the French state, Paris city hall and heritage defence groups before approval was granted in June.
   
But even then, critics feared the proposals -- which still involved destroying a staircase, putting in new elevators and an underground car park -- would wreck one of Paris' best-preserved mansions.
   
Tuesday's ruling does not challenge the restoration part of the prince's plans, which plans for key rooms to be renovated in keeping with the original, but it blocks the wider 40-million-euro plan to modernise the building.
   
Ranged around a central courtyard garden, the Hotel Lambert has fallen into disrepair, with its grand staircase twisted out of shape, sections of floorboard rotting through and part of its roof timber worn out.
   
But it is still considered one of the finest examples of mid-17th-century domestic French architecture, complete with mural paintings by Charles Le Brun and other masters of the day.