President Emmanuel Macron described the theft as an "attack" on French heritage.

As the alarms sounded at the Louvre Museum on Sunday morning, four suspects took off on two motorbikes, winding their way through central Paris, allegedly carrying with them a haul of "priceless" jewelry once worn by queens and royals.
The suspects were last seen speeding southeast on Highway A6 out of Paris and in the direction of Lyon, according to investigators.
About 24 hours after the brazen theft of some of the most recognizable pieces of glittering French heritage, which were taken during daylight hours from the world's most-visited museum, a nationwide manhunt and investigation are in full swing, according to state and law enforcement officials.
"The theft committed at the Louvre is an attack on a heritage that we cherish because it is our history," President Emmanuel Macron said on social media on Sunday.

He and other French officials vowed that the pieces would be returned and the suspects apprehended. The museum closed on Sunday morning as police swarmed the area in search of suspects and evidence.
"Following yesterday's robbery at the Louvre, the museum regrets to inform you that it will remain closed to the public today," officials said in an update on social media on Monday. "Visitors who have already booked tickets will be refunded."
As the investigation to identify the culprits continued, a crisis meeting took place at the Interior Ministry that included Culture Minister Rachida Dati as well with the Banditry Repression Brigade (BRB), the special policeunit of the Ministry of Interior that investigates major art thefts, authorities said.
The suspects arrived in pairs, with two in a truck and two riding motorbikes, authorities said on Sunday. The truck was equipped with a moving ladder, a "mobile freight elevator" of the type city furniture movers sometimes use, Paris police said.
The suspects allegedly parked the truck on a road that runs along the side of the museum, near the Seine, police said.
They were dressed as construction workers, wearing yellow and orange vests, police said. The thieves took the time to secure the area near the truck by placing orange construction cones around it, police said.
Two of the thieves then used the ladder to get up to the second floor, climbing onto a thin balcony with a metal railing outside the museum's Apollo Gallery, where some of the French crown jewels were kept, according to police.

Once they had used an angle grinder to open the window, they clambered through it, police said. Their entrance triggered the alarm, which was still sounding when they left, the museum said in a statement.
"Inside, they then smashed two display cases, 'Napoleon jewels' and 'French crown jewels,' using the angle grinder and stole numerous pieces of high-value jewelry," police said.
When they left through the same window about seven minutes later, they had with them eight pieces of jewelry of "inestimable" value, as France's interior minister described them on Sunday. Other officials, including Rachida Dati, the culture minister, described them to French media as "priceless."
According to the French Ministry of Culture, among the items stolen was a diadem, or crown, from the collection of Queen Marie-Amelie and Queen Hortense; an emerald necklace and a pair of emerald earrings from the collection of Marie-Louise, Napoleon's second wife; and a large bow brooch from Empress Eugenie's bodice.
Police believe the team of bandits made some mistakes, although they conceded that the heist seemed well planned. One of the mistakes the thieves made was either accidentally dropping or abandoning one of the precious pieces, Empress Eugenie's pearl tiara, which, according to the Louvre, is composed of 212 pearls and nearly 2,000 diamonds.
The Eugenie crown was left behind with a blanket, the two angle grinder, a walkie talkie, gloves, gasoline and blowtorch, investigators said.
Investigators are combing through security video to glean any information about the thieves, officials said. The security cameras captured the four robbers trying to set fire to the mobile freight elevator used in the heist before jumping on their motorbikes and fleeing, according to the Paris Prosecutor's Office.
Officials at the museum said in a statement that an investigation had been launched into the "organized theft and criminal conspiracy to commit a crime."
The CGI Group, an Israeli security firm, has been brought in to by the Louvre and with permission from the Culture Ministry to work on the case, investigators said. The CGI Group gained notoriety in 2019 when it helped solve the Dresden Green Vault burglary, where jewelry and diamonds worth more than $130 million were stolen from the Dresden Castle in Germany.
Laure Beccuau, the Paris prosecutor, told a local TV station on Sunday that about 60 investigators were working on the case, showing "total determination" to find those responsible.
As of Monday morning, police had not yet said whether they had any leads on the possible identities of the suspects.
Officials said the suspects appeared to have been professionals. Beccuau said officials hadn't ruled out possible foreign involvement, but also that investigators were treating it as a domestic case at the moment.
"Everything is being done to apprehend the perpetrators of this unacceptable act as quickly as possible," Laurent Nunez, the interior minister, said on Sunday.
ABC News' Will Gretsky, Somayeh Malekian, Hugo Leenhardt, Camilla Alcini, Victoria Beaule, Dragana Jovanovic and Joe Simonetti contributed to this report.