Produced by Margot Tiounine, edited by Richard Topping, filmed by Dominic Egan
You can enable subtitles (captions) in the video player
This is the first time the reconstruction team at Notre-Dame has opened the cathedral doors to the media. In April, the world watched as the Gothic masterpiece went up in flames.
A massive effort is now under way to secure the building structure and clear debris.
Over 40 teams are currently on site for the reconstruction, with four lead architects, and between 60 and 150 workers.
A billion euros was pledged for the reconstruction effort, but only a fraction has so far been received.
These are the pieces of the jigsaw that need to be put back together.
The first stages in Notre-Dame's reconstruction will see architects and engineers work together from a digital copy of the building, made possible by 3D laser scanning.
This is Sainte-Chapelle, another masterpiece of the Gothic era, located just a short stroll from Notre-Dame. Benjamin has been tasked to scan it as part of a global effort to preserve landmarks across the country.
This method creates an exact copy of a building in the event of destruction or fire.
Such innovation continues today.
The scan provides the foundation for the rebuild of Notre-Dame.
This modelling can be used by every single worker on the construction site, and the different teams share the modelling in a common database. Then construction can begin in earnest.
The reconstruction project is expected to take at least five years.
There are still questions over the stability of the vaults in the cathedral, and how the reconstruction will look is yet to be decided. The battle to save Notre-Dame has only just begun.