The Louvre's cameras failed to detect burglars in time to prevent their audacious daylight heist of some of France's crown jewels, the museum's director has said.
The thieves used a crane and smashed an upstairs window before stealing jewels worth an estimated 88 million euros ($157 million).
They then escaped on motorbikes.
News of the theft, which occurred steps away from the Mona Lisa, reverberated around the world and prompted soul-searching in France over what some viewed as a national humiliation.
Louvre director Laurence des Cars told senators that she had offered her resignation, but it had been refused by Culture Minister Rachida Dati, who has also come under fire after the robbery.
"Despite our efforts, despite our hard work every day, we were defeated," Ms des Cars told a senate committee.
Many in France and around the world have been baffled as to how four hooded assailants were able to drive up to the world's most visited museum, smash a second-floor window and make off with a handsome booty without getting caught.
"We did not detect the thieves' arrival early enough," Ms des Cars said.
She said the exterior security cameras did not offer full coverage of the museum's facade and added that the window through which the thieves broke in was not monitored by CCTV.
Ms des Cars said she had repeatedly raised the issue of security at the centuries-old building.
"The warnings I had been sounding came horribly true last Sunday," she said.
Ms des Cars pledged to establish no-parking perimeters in areas around the Louvre, upgrade the CCTV network.
She said she would also ask the interior ministry to set up a police station inside the museum.
Gone in four minutes
According to authorities, the thieves spent less than four minutes inside the Louvre on Sunday morning before making their getaway.
Alarms had gone off, drawing agents to the gallery and forcing the intruders to bolt.
The Louvre, which has reopened, said that no uniformed police were posted in the corridors.
The day was fully booked and access was limited amid school holiday demand.
"I didn't notice extra security — guards as always, and no police inside," 29-year-old Madrid resident Tomás Álvarez said.
"It felt like a normal day."
The jewels remain missing and the thieves are still at large.
What was stolen?
The thieves made away with eight items, including a sapphire diadem, a necklace and a single earring from a set linked to 19th-century queens Marie-Amélie and Hortense.
They also stole an emerald necklace and earrings linked to Empress Marie-Louise, Napoleon Bonaparte's second wife, as well as a reliquary brooch.
Empress Eugénie's diamond diadem and her large corsage-bow brooch are also gone.
Eugénie's emerald-set imperial crown, encrusted with more than 1,300 diamonds, was later found outside the museum.
It was damaged but restoration should be achievable.
Paris is home to some of the world's best-known cultural institutions, including museums such as Orsay, Pompidou and Quai Branly.
At least four French museums have been robbed in the last two months, according to media reports.
AP/Reuters
