Labour leaders said the strike vote was unanimous and it was not immediately clear whether the work stoppage will last longer than one day.
The Louvre in Paris, the world's most-visited museum, was closed on Monday after workers walked out on strike in protest against working conditions and other complaints, dealing another blow to the landmark after an embarrassing jewellery heist in October.
The CFDT union said the vote was taken at a meeting of 400 workers on Monday morning and that they decided to strike for the day.
Striking workers with flags, banners and placards blocked the museum’s iconic glass pyramid entrance.
An updated notice on the Louvre's website said it was "exceptionally" closed for the day and that ticket holders would be reimbursed.
Labour leaders said the strike vote was unanimous. It was not immediately clear whether the work stoppage will last longer than one day.
The Louvre is closed on Tuesdays. Employees could meet again on Wednesday to decide whether to stay out or go back to work.
"It's really sad, because I was really looking forward to this," said Lindsey Hall, a disappointed would-be visitor from Sacramento, California.
She had been planning to enjoy the museum's huge collection of art and artefacts with a friend, describing it as "one of those life experiences you crave."
"This is just an epic collection of art and something that every human should see," she said. "I can see the other side of it, like if you are the person that works in the museum and how that can be, like day after day after day."
An obstacle course
The strike vote followed talks last week between labour unions and government officials including France's Culture Minister Rachida Dati. Labour leaders said the talks had not alleviated their concerns about staffing and financing for the museum that welcomes millions of visitors each year.
"Visiting the museum has become an obstacle course," said Alexis Fritche, general secretary of the culture wing of the CFDT union.
For employees, the brazen daylight jewel heist crystallised long-standing concerns that crowding and thin staffing are undermining security and working conditions at the Louvre.
Police arrests subsequently snared the entire four-man team alleged to made off with €88 million worth of jewels.
The gang used a basket lift to reach the Louvre's facade, forced a window open, smashed display cases and fled with pieces of the French crown jewels.
A Senate inquiry released last week said the thieves escaped by barely 30 seconds and blamed broken cameras, outdated equipment, understaffed control rooms and poor coordination that initially sent police to the wrong location.
In a statement, the CFDT said employees want more security staff and a welcoming visitor experience, improved working conditions, stable, long-term budgets for the Louvre and leadership that "truly listens to staff".
Yvan Navarro of the CGT union complained that staff numbers have continued to decline while visitor numbers have increased.
"People come to Paris to visit the museums. So the visitor numbers go up, the tariffs and the prices go up, because everything is becoming more expensive but the salaries and the numbers of staffers don't go up so obviously you reach a point like today, a day of anger," he said.
In their notice of open-ended strike action to Dati last week, the CFDT, CGT and Sud unions said the Louvre was in "crisis," with insufficient resources and "increasingly deteriorated working conditions."
The French Culture Ministry said on Sunday that it had tasked Philippe Jost, who oversaw reconstruction of Notre Dame Cathedral after the 2019 fire, with a mission to propose a deep reorganisation of the Louvre following the findings of an administrative inquiry.
It said Jost will offer recommendations by the end of February. He will work with Louvre director Laurence des Cars, who previously described the heist as a "terrible failure".
