The swollen Seine River continues to rise, spilling into Paris streets and forcing one landmark after another to shut down as it surged to its highest levels in nearly 35 years.
Across the French capital, museums, parks and cemeteries are being closed as the city braces for possible evacuations.
The Seine is expected to peak in Paris later on Friday at about 5 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 Azouley, speaking to journalists outside the world-famous 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 some 250,000 artworks from basement storage areas at risk of flooding to safer areas upstairs.
Nearly a week of heavy rain has led to serious flooding across a swathe of Europe, leaving 15 people dead and others missing.
Although the rain has tapered off in some areas, flood waters are still climbing. Traffic in the French capital ground to a halt as flooding blocked roads and several Paris railway stations shut down.
Basements and homes in the capital's affluent 16th district began to flood on Friday afternoon as the river kept rising, and authorities were preparing possible evacuations in a park and islands on Paris's western edge.
In addition to the Louvre, the Orsay museum, home to a renowned collection of impressionist art on the left bank of the Seine, was also closed on Friday to prepare for possible flooding. The Grand Palais, which draws 2.5 million visitors a year, was also shut down. The closures are highly unusual.
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.
Elsewhere in Europe, authorities are counting the cost of the floods as they waded through muddy streets and waterlogged homes.
German authorities said the body of a 65-year-old man was found overnight in the town of Simbach am Inn, bringing the country's death toll over recent days to 10.
France's Interior Ministry also reported the death of a 74-year-old man who fell from his horse and drowned in a river in the Seine-et-Marne region east of Paris, the second death in France.
In eastern Romania, two people died and 200 people were evacuated from their homes as floods swept the area, including one man who was ripped from his bicycle by a torrent of water in the eastern village of Ruginesti.
In Belgium, rescue workers found the body of a bee keeper who was swept away by rising waters while trying to protect his hives in the village of Harsin.
The German Insurance Association estimates this week's flooding has caused some 450 million euro in damage in the state of Baden-Wuerttemberg alone.
The foul weather has added to the major travel disruptions France is already experiencing, after weeks of strikes and other industrial actions by workers upset over the government's proposed labour reforms. French rail company SNCF said the strikes had led to the cancellation of some 40% of the country's high-speed trains.
In addition, French energy company Enedis said more than 20,000 customers are without power to the east and south of Paris because of flooding.
Outside the Louvre, tourists expressed understanding at the museum's closure.
"It's good that they are evacuating the paintings. It is a shame that we couldn't see them today, but it's right that they do these things," said Carlos Santiago, visiting from Mexico.
Paris is measuring river levels using an unusual method called the Austerlitz scale. It involves comparing the surface level with an underwater sensor slightly below the surface at the Austerlitz Bridge, said regional environment director Jerome Goellner.
In normal times, the river level is between 1 metre and 2 metres on the Austerlitz scale, he said, a system used out of historical habit so one flood could be compared to another. But a piece of litter trapped in the sensor led authorities to undercount the rise of the Seine earlier this week, he said.
The Seine has so far risen about 4.5 metres from its typical position following days of heavy rain. Mr Goellner said it is not possible to put a precise time on the peak but "we're near the maximum".