The swollen Seine River keeps rising, spilling into Paris streets and forcing one French landmark after another to shut down as it surges to its highest levels in nearly 35 years.
Across the city, museums, parks and cemeteries shut down as the city braced for evacuations.
The Seine was expected to peak in Paris on Saturday at about five metres above normal.
Authorities shut the Louvre museum, the national library, the Orsay museum and the Grand Palais, Paris' striking glass-and-steel topped exhibition centre.
"We evaluate the situation for all the [cultural] buildings nearly hour-by-hour," said Culture Minister Audrey Azoulay, speaking to journalists outside the Louvre.
"We don't know yet the evolution of the level of the Seine River in Paris."
At the Louvre, home to Leonardo da Vinci's Mona Lisa, curators were scrambling to move about 250,000 artworks from basement storage areas at risk of flooding to safer areas upstairs.
The Louvre will stay closed through Tuesday (local time) and the Orsay Museum, known for its impressionist art, closed for the weekend.
Nearly a week of heavy rain has led to serious flooding across Europe, leaving 16 people dead and others missing.
Although the rain has tapered off in some areas, floodwaters are still climbing and could take weeks to clear and authorities urged vigilance. Traffic in the French capital was snarled as flooding choked roads and several Paris railway stations shut.
Basements and apartments in the capital's well-to-do 16th district began to flood on Friday as the river crept higher, and authorities evacuated a campground in the Bois de Boulogne park on the western edge of the city.
French authorities activated preliminary plans to transfer the French presidency and other sensitive sites to secure places in case of flooding.
The SGDSN security agency says the National Assembly, or lower house of Parliament, and the Foreign Ministry were at greater risk.
The Louvre said the museum had not taken such precautions in its modern history - since its 1993 renovation at the very least. Disappointed tourists were being turned away but most were understanding.
"It's good that they are evacuating the paintings. It's a shame that we couldn't see them today, but it's right that they do these things," said Carlos Santiago, visiting from Mexico.