The French embassy in Dublin has said it has received "hundreds of thousands of messages" of support, following the fire at Paris' Notre Dame Cathedral.
Firefighters have said the blaze which destroyed parts of the medieval building in Paris on Monday night has been fully extinguished.
The main stone structure - including its two towers - have been saved, but the spire and roof collapsed.
One firefighter has been seriously injured and local media say police are treating the blaze as an accident.
French President Emmanuel Macron has said the country will rebuild the cathedtral.
A fund is being launched to help pay for what could be a massive reconstruction project.
Mr Macron said he was "so sad tonight to see this part of all of us burn" and declared a national emergency.
Speaking from the scene in Paris, he expressed sympathy with Catholics "around the world" following the "terrible tragedy" but added the worst had been avoided.
He vowed to launch an international fundraising campaign for the cathedral so the world could rebuild Notre Dame together.
A French firefighter official confirmed Notre Dame's structure and two towers had been saved from total destruction.
Lionel Paradisi-Coulouma is deputy head of mission at the French embassy in Dublin.
He told Newstalk Breakfast: "It was only yesterday evening it was a feeling of immense sadness in front of such tragedy.
"Notre Dame is the cathedral of all French people, including - as President Macon said yesterday - those who never visited it in fact.
"It's as well the witness of French history and world history - really a monument to all culture and heart.
"An essential monument for Catholics, as you know, but also for Parisians, for French and for people world-wide."
"President Macron once again told only yesterday evening that Notre Dame de Paris is really our history, our literature, where we lived our greatest moments.
"The liberation of Paris... Napoleon's consecration, and the amazing works of Victor Hugo, of the poet Charles Péguy as well.
"The history of Notre Dame is totally intertwined with the French history as a whole".
"We will rebuild together Notre Dame - it was absolutely important to share this message of hope - and saying yes, Notre Dame will be rebuilt".
"We are very moved by this wave of international solidarity - and many, many thanks to the Irish people, to the Irish authorities for an incredible support (and) solidarity.
"We've received hundreds of thousands of messages at the embassy, saying 'may she rise again'".
Taoiseach Leo Varadkar said it was "Devastating for the people of Paris".
Terrible to see #NotreDame ablaze tonight. Such an iconic cultural landmark. Devastating for the people of Paris who are watching history burning.
— Leo Varadkar (@LeoVaradkar) April 15, 2019
While President Michael D Higgins expressed his hope that the landmark would survive "this latest terrible catastrophe."
"The Notre Dame Cathedral has suffered many instances of catastrophic damage over the centuries, and it is my hope that it will survive this latest terrible catastrophe."
Full statement at https://t.co/FOm2nOjo6F pic.twitter.com/2xqwjjE32q
— President of Ireland (@PresidentIRL) April 15, 2019
US President Donald Trump also expressed his sadness on social media, saying it was "so horrible to watch the massive fire".
So horrible to watch the massive fire at Notre Dame Cathedral in Paris. Perhaps flying water tankers could be used to put it out. Must act quickly!
— Donald J. Trump (@realDonaldTrump) April 15, 2019
Mr Trump later simply tweeted: "God bless the people of France!"
The Louvre Museum, another famous and popular tourist attraction in Paris, tweeted that the fire was "a tragedy for the world heritage of mankind" and expressed its "profound emotion and its strong solidarity with the teams that are currently fighting against the flames".
L’incendie qui a frappé la cathédrale Notre-Dame de Paris est un drame pour le patrimoine mondial de l’Humanité. Le musée du Louvre exprime sa profonde émotion et sa plus vive solidarité avec les équipes qui luttent actuellement contre les flammes.
— Musée du Louvre (@MuseeLouvre) April 15, 2019
Several of France's richest people and companies are to donate towards the rebuilding efforts.
French billionaire François-Henri Pinault, who is married to the actress Salma Hayek, has said he will donate €100m to help to "completely rebuild Notre Dame".
Pinault is the chairman and CEO of the Kering group, which owns such brands as Gucci, Yves Saint Laurent and Alexander McQueen.
He is also president chairman of Artemis, the holding company that controls the assets of the Pinault family.
He is thought to be worth more than €22bn.
In a statement, he said: "This tragedy strikes all the French and beyond all those who are attached to spiritual values. Faced with such a tragedy, everyone wants to revive this jewel of our heritage as quickly as possible.
"My father and I have decided to release from the funds of Artemis a sum of 100 million Euros to participate in the effort that will be necessary for the complete reconstruction of Notre Dame."
LVMH chief executive Bernard Arnault has offered €200m to reconstruct the "symbol of France".
"The Arnault family and the LVMH group would like to show their solidarity at this time of national tragedy, and are joining up to help rebuild this extraordinary cathedral, which is a symbol of France, of its heritage and of French unity," a statement said.
The brands of LVMH include Louis Vuitton, Dior and Givenchy.
The homepage of the group's website has also been changed to show an image of the famous cathedral.
"In the wake of this national tragedy, the Arnault family and the LVMH Group pledge their support for #NotreDame. They will donate a total of 200 million euros to the fund for reconstruction of this architectural work, which is an integral part of the history of France." pic.twitter.com/utvJT8xJht
— LVMH (@LVMH) April 16, 2019
While Patrick Pouyanné, chief executive of energy company Total, said his company would give €100m towards the cathedral's reconstruction.
France's Fondation du Patrimoine, a private organisation which works to protect French heritage, said it would be starting an international appeal.
It tweeted: "For Our Lady to be reborn from her ashes we are launching an international appeal. All donations received will be paid in full to the restoration site."
Pour que Notre-Dame puisse renaître de ses cendres nous lançons un appel international. Tous les dons reçus seront intégralement versés au chantier de restauration. ➡https://t.co/QAB3kEZRlq pic.twitter.com/XRIObHFLbW
— Fondation du patrimoine (@fond_patrimoine) April 15, 2019
The cost of rebuilding the cathedral is expected to run into the billions of Euros.
Video filmed by witnesses showed the moment the historic landmark's steeple was consumed by flames before toppling over.
Hours later the area where the spire had once been was still seen burning, with sparks falling from the cathedral's vaulted ceiling.
One described people "howling and gasping" as they watched the destruction unfold.
Another witness said they saw a fire breaking out in one of the cathedral's towers.
"Everything is burning, nothing will remain from the frame," a Notre Dame spokesman told local media on Monday night.
The city's deputy mayor said Notre Dame had suffered "colossal damages" and emergency services were trying to salvage the art and other priceless pieces stored inside it.
A firefighter at the scene confirmed all efforts were being put into saving artwork at the back of the cathedral and stopping the northern tower from collapsing.
Its priceless treasures include the crown of thorns - a Catholic relic which is only occasionally displayed.
Paris prosecutors have opened an investigation into the fire. They have ruled out arson and possible terror-related motives and instead think the blaze was started by accident.
UNESCO's director Audrey Azoulay said there was "huge emotion" and the organisation "stands alongside France to help safeguard and rebuild this inestimable piece of our heritage".
Former US president Barack Obama also wrote on Twitter: "Notre Dame is one of the world's great treasures, and we're thinking of the people of France in your time of grief.
"It's in our nature to mourn when we see history lost - but it's also in our nature to rebuild for tomorrow, as strong as we can."
The Vatican, the head of the Catholic Church, said it was praying for French firefighters.
And the Archbishop of Paris called on all priests in the city to ring their church's bells as a gesture to Notre Dame.
It was in the midst of renovations, with some sections under scaffolding, while bronze statues were removed last week for works.
The attraction is visited by millions of tourists every year and translates in English as "Our Lady".
Its first stone was laid in 1163 in the reign of Louis VII, as the medieval city of Paris was growing in population and importance, becoming the political and economic centre of the kingdom of France.
Construction continued for much of the next century, with major restoration and additions made in the 17th and 18th century.
The 387 steps up to the towers take visitors past the gallery of chimeras, mythical creatures typically composed of more than one animal.
The cost of trying to maintain Notre Dame has spiralled over the years and in the past the French government has looked to the private sector to help finance its upkeep.
Additional reporting: IRN