Louvre staff closed the Paris museum on Monday in protest over working conditions and long-standing complaints.
Labour leaders said 400 employees voted unanimously to strike during a morning meeting.
The museum normally closes on Tuesdays, but employees may decide Wednesday whether to continue the stoppage.
Striking workers blocked the iconic glass pyramid with flags, banners, and placards.
The Louvre posted an updated notice online confirming the exceptional closure and promising ticket refunds.
Thousands of visitors faced disruption, including Lindsey Hall from Sacramento, California, who called the museum a “life experience you crave.”
Visitors sympathize amid disappointment
Hall said the collection of art is epic and every person should experience it.
She said she understood how daily pressures could exhaust museum employees.
Other tourists shared similar frustration while also recognizing the staff’s challenges with overcrowding and thin staffing.
Staff cite safety, funding, and staffing issues
Union leaders said talks with Culture Minister Rachida Dati failed to resolve core concerns about finances and staffing.
Alexis Fritche of CFDT said, “Visiting the museum has become an obstacle course” due to staff shortages and overcrowding.
Employees say the October jewel heist highlighted security weaknesses and understaffed control rooms.
Police later arrested four suspects accused of stealing €88 million in crown jewels.
The thieves used a lift, forced a window, smashed display cases, and escaped by 30 seconds.
A Senate inquiry blamed broken cameras, outdated equipment, and poor coordination for the security failure.
CFDT said workers demand more security, improved conditions, stable budgets, and leadership that listens.
CGT union official Yvan Navarro said staff numbers have declined even as visitor numbers and ticket prices rise.
Unions called the Louvre “in crisis” in a notice of open-ended strike action to Dati last week.
The French Culture Ministry appointed Philippe Jost, who rebuilt Notre Dame after the 2019 fire, to lead a major reorganisation.
Jost will work with Louvre director Laurence des Cars and provide recommendations by the end of February.
Des Cars previously called the jewel heist a “terrible failure” and supported measures to improve security and staffing.
