Water levels in the River Seine in Paris are still rising despite France's unseasonable spate of heavy rain beginning to taper off, officials have said.
Traffic in the capital was snarled up as flooding choked roads and several Paris railway stations were shut.
The country's environment ministry said the Seine had not reached such levels since 1982.
The Louvre Museum was closed on Friday as staff worked to remove artworks from rooms threatened by the rising water.
French President Francois Hollande has said a "natural disaster" will be formally declared next week in a Cabinet meeting for areas most affected by the flooding that has hit Paris and France's central regions.
French energy company Enedis said more than 20,000 customers were without power on Friday as the result of flooding.
In a text message, the company said the blackouts were concentrated in the departments of Seine et Marne and Essonne - to the east and south of Paris, respectively.
Meanwhile, German officials have recovered the body of a sixth person who died in this week's flooding in Bavaria, near the Austrian border.
Authorities said the 65-year-old man's body was found overnight in the town of Simbach am Inn, which was inundated on Wednesday.
Now that floodwater has receded in the area, the search continues for other missing people.
Local police told the dpa news agency on Friday that they were still trying to locate an elderly couple in Simbach.
That brings the total of people killed in flooding in Germany over the last week to 10 - including four in Baden-Wuerttemberg, to Bavaria's west, in flooding on Sunday and Monday.
Elsewhere, authorities said two people died and 200 people were evacuated from their homes as floods swept parts of eastern Romania.
The interior ministry said 7,000 firefighters, police and others had been dispatched overnight on Friday to help in flood rescue efforts.
The ministry said in a statement that a man died after a torrent of water knocked him off his bicycle in the eastern village of Ruginesti. In Bacau county, in eastern Romania, another man was found drowned.