A gallery attendant on duty at the Louvre when thieves broke in and stole eight of France's crown jewels has said no-one could have been prepared for what unfolded as visitors began to arrive on Sunday morning.

All of a sudden we heard a huge noise, she told radio station France Inter, in the first account given by an attendant at the scene.

The unnamed attendant and two colleagues initially thought the noise to be an angry visitor, but it was not a normal sound: It was a dull, slightly metallic noise. It was, in fact, the moment thieves had used an angle grinder to burst through a reinforced window into the Gallery of Apollo, where the Louvre's collection of historic jewelry is kept.

Within eight minutes, the gang seized treasures, including a necklace that belonged to Napoleon's wife Empress Marie-Louise and a diadem of Napoleon III's wife Empress Eugenie, worth an estimated total of €88m (£77m).

The thieves used a mechanical ladder to access a first-floor balcony. Two tourists ran towards them in panic, leading the attendant to yell for her colleagues to evacuate. I saw one of the criminals turn around with something that looked to me like a chainsaw, then I yelled at my colleagues to get out, she recalled.

They managed to raise the alarm and evacuate visitors while securing the neighboring galleries. Reflecting on the incident, she remarked on how unbelievable it was that the display cases had been breached, as they never anticipated such a risk.

Security measures are now under scrutiny. The museum's director reported that the gang had ruptured their vehicle's fuel tank and had a blowtorch nearby, suggesting they planned to set fire to escape evidence.

Following the incident, museum officials fear for the condition of the stolen pieces, particularly Empress Eugenie’s crown, which showed signs of damage. The initial investigation has raised concerns about the security lapses at the Louvre, where funding and inadequate camera coverage at critical points have been evident.