By Richard Lough and Caroline Pailliez
PARIS (Reuters) - France will open the redesign of Notre-Dame de Paris cathedral's historic spire to international architects after Monday night's catastrophic blaze that gutted the centuries-old roof and sent the towering spire crashing through the vaulted ceiling.
The government's announcement on Wednesday added to a question many are asking as France grieves for its national symbol - whether the familiar outline at the heart of the capital should be restored as it was or given a modern twist.
President Emmanuel Macron pledged in a prime-time address to the nation on Tuesday that Notre-Dame would be rebuilt within five years. Tycoons, international firms, local authorities and individuals have promised financial and expert help - with a total of nearly 900 million euros (780.05 million pounds) pledged by Wednesday.
The cathedral was built over nearly 200 years starting in the middle of the 12th century, although it was only in the mid 1800s that architect Eugene Viollet-le-Duc added the lead-covered spire during restoration work.
"The international competition will allow us to ask the question of whether we should even recreate the spire as it was conceived by Viollet-le-Duc," Prime Minister Edouard Philippe said.
"Or whether, as is often the case during the evolution of heritage, we should endow Notre-Dame with a new spire that reflects the techniques and challenges of our era."
Monday's inferno devastated a world treasure, prompting an outpouring of collective sorrow and soul-searching in France over whether to recreate the destroyed oak-framed roofing and spire or adapt the cathedral to the 21st century.
As Philippe spoke, firefighters were working to stabilise a fire-ravaged pinnacle that houses one of Notre-Dame's 13th-century stained-glass rose windows.
There was no immediate danger that the structure would topple but statues were also being removed to reduce the risk of movement, the fire service's spokesman said.
"Today, there is no risk of collapse. Our priority is to stabilise the pinnacles which are weakened, since they are no longer held up by the roof and its frame," Lieutenant-Colonel Gabriel Plus told Reuters.
U.S. President Donald Trump had a phone call with Pope Francis, head of the Roman Catholic Church, on Wednesday to offer condolences over the fire. Trump said in a tweet he had offered the help of "our great experts on renovation and construction".
REPLICATE OR RESHAPE?
It was not yet known what caused the blaze.
The city's public prosecutor, Remy Heitz, said on Tuesday there was no sign of arson and it was likely to have been the result of an accident. Some 50 people were working on what would be a long and complex investigation, he said.
Passers-by laid flowers on bridges crossing the Seine River as Parisians gave thanks to see the bell towers standing valiantly after the fire.
Notre-Dame is not the first French cathedral to suffer a devastating fire. Among past catastrophes, a 1972 fire engulfed the roof of Saint-Pierre-et-Saint-Paul de Nantes. Concrete was used in the subsequent reconstruction of gables and roof beams.
"What's extraordinary is that Notre-Dame's roof lasted until 2019," Francois Chatillon, a prominent architect and specialist in historic monuments, told Reuters.
In a city that has a strong tendency to preserve and initially balked at the Eiffel Tower and the Louvre Museum's glass pyramid, before they too became nationally loved, altering the cathedral's outline could prove unpopular.
Benjamin Mouton, Notre-Dame's affiliated architect between 2000-2013, said it was pointless to be dogmatic about using the same materials for the restoration of a building that has already been "heavily altered, modified and reinforced".
"On the other hand, we must recreate the cathedral's silhouette and rebuild the spire. That to me is indispensable," said Mouton, who logged each of the timber beams in Notre-Dame's attic that was dubbed the "forest".
NEW TAX BREAK FOR SMALL DONATIONS
Concerns over the cathedral's structural soundness have prevented investigators from entering Notre-Dame's main nave to assess damage at ground level.
As the scale of damage was revealed, billionaires and corporate giants lined up to pledge huge donations. Their largesse raised questions among some French people over whether they had hidden motives such as seeking tax breaks.
Philippe said his government would draft new legislation to introduce a 75 percent tax deduction on private donations up to 1,000 euros. The deductible will remain at 66 percent for bigger sums.
The cathedral has been at the centre of a long-running financing dispute and pleas from the Church for more cash.
(Reporting by Jean-Baptiste Vey, Julie Carriat, Richard Lough, Pascale Denis and Marine Pennetier; Writing by Richard Lough; Editing by Frances Kerry)