Visitors to Paris hoping to see the Mona Lisa this summer, beware. Only those holding a pre-booked ticket with an all-important timed slot were given access to the Louvre last week after its most famous painting was moved to a different gallery. The temporary rehang has thrown the world’s most popular art museum’s crowd-control measures out of whack.

“I have never seen such chaos,” an irate tour guide of 15 years, Isabella, tells the French paper Le Parisien. “I did not think it was possible to show such amateurism.” She added that last week her usual two-hour tour of the museum took twice as long because of bottlenecks, even though the group had booked tickets in advance. 

Leonardo da Vinci’s masterpiece was moved to a new gallery on July 16 while the Salle des États is being revamped. The painting is due to remain, bulletproof glass and all, among paintings by Rubens in the museum’s Galerie Médicis until October.

The Louvre attracts around 10 million visitors a year and can accommodate some 30,000 to 50,000 people a day, 80 percent of whom come to see the Mona Lisa. While the Médicis gallery is large, unlike the Mona Lisa’s traditional home the room is accessible only through a single door reached by way of two escalators leading to the top floor of the Richelieu wing.

This created a series of bottlenecks, leading to a line forming right through the heart of the museum. At peak times the line began in the museum’s entrance hall under the Pyramid. Visitors who managed to reach the gallery were reported to have been shouted at to move along immediately, with security guards instructed to block the view of any dawdlers until they exited the space.

The issue was compounded by Paris’s record-breaking heatwave, which drove a higher number of people to the museum. Officials began turning away those who had not booked tickets with a timed slot online to control the flow of crowds, all the while continuing to sell tickets from its kiosk on site, and online. Hundreds of French and foreign tourists who did not reserve a timed ticket, as well as those who usually access the museum for free, were disappointed.

The museum claims to have got the crowd flow under control, with a museum spokesman telling the French newspaper that the situation was resolved within three days. However, as recently as Monday visitors with general admission tickets were still being turned away. This morning, the Louvre’s website was also down, possibly due to a rush of traffic to the site.

“There was a real lack of foresight, and consultation with the different tourist agencies,” Corinne Menegaux, the general director of Paris’s tourism office, said. Despite hundreds of visitors with tickets being turned away from the museum, Menegaux’s office has only received about a dozen official complaints, and just four people have taken up their offer to refund disappointed visitors the cost of their $17 tickets.

In October, the museum is making pre-booked, timed, tickets compulsory for the first time when its blockbuster Leonardo exhibition opens in the Hall Napoléon. The Mona Lisa will not be part of the special exhibition to mark the 500th anniversary of the artist’s death due to the limited capacity of the space.