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The Queen, Prince Philip and Prince Harry were among those attending the ceremony.
An architectural expert who helped restore Windsor Castle after its fire has offered to support those tasked with rebuilding Paris's Notre Dame Cathedral.
Francis Maude, director of Donald Insall Associates which co-ordinated the reconstruction of the Queen's Berkshire home after fire destroyed 115 rooms in 1992, said: "If there's a way in which we can support the work that they do, we'd be really delighted to be able to help and share our knowledge the best we can."
Mr Maude said the rebuilding of the historic French landmark, which was devastated by a fire on Monday, could be achieved.
"It's a tragedy when an event like this happens. It's an easier thing to be very downcast when you start looking at what has been lost," he said.
"But we do know, because we've seen it elsewhere, in the aftermath of wars and indeed at Windsor Castle here, that restoration is possible." He added: "The challenge is to try and retain the authenticity of the place - the historic fabric."