There are fears that more heavy downpours forecast across a swathe of Europe may worsen floods that have already left five people dead.
Four people drowned in southern Germany, with two more missing and thousands of homes without electricity.
Some parts of central France have seen their worst floods in over a century. The body of an elderly woman was found in her flooded home.
Thousands were evacuated in France and thousands of emergency call-outs made.
Heavy showers are forecast right through the weekend across a band of central Europe from France to Ukraine, with as much as 50mm (2in) of rain falling in some parts in just a few hours.
‘Totally under water’
After a day of respite on Wednesday in central France, the region is braced for a further rise in already exceptionally high river levels.
The Loiret department, south of Paris, is on red alert, with seven others one level lower.
Nearly 10,000 homes are without electricity.
Prime Minister Manuel Valls visited the stricken town of Nemours on Wednesday.
Its mayor said 3,000 people had been evacuated from the town centre.
The town’s Loing river, a tributary of the Seine, now has levels not seen since the devastating floods of 1910.
“The centre of town is totally under water. All the businesses have been destroyed,” said mayor Valerie Lacroute.
Fire services found the body of an 86-year-old woman floating in her home in Souppes-sur-Loing. The town of Montargis was also badly affected, with one road turned into a canal.
Six weeks’ worth of rain have fallen in three days in the Loiret department.
Some roads and rail lines have been cut off, and schools in badly affected areas closed.
The level of the Seine in Paris reached 4.45m (15ft) on Wednesday evening and could rise to 5.7m over the coming days, requiring “heightened vigilance”, the mayor said, although it remains well below the 8.62m of the historic 1910 floods.
No relief in sight – Jacob Cope, forecaster, BBC Weather Centre
A large area of low pressure has been bringing heavy showers to much of Europe recently and this weather pattern shows no signs of shifting in the next few days.
A large swathe of the continent from central France through Belgium, Germany through southern Poland to Romania, Moldova and Ukraine looks set for further heavy, thundery showers to end the week and through the weekend.
These showers are likely to be slow moving and have the potential to be long-lasting with large hailstones, frequent lightning, gusty winds and flash flooding with as much as 50mm (2 in) of rain in some parts in just a few hours.
Floods also cut off the getaway of two shop robbers in the town of Fleury-les-Aubrais. They fled their car and tried to make a swim for it, but were arrested.
The deadliest incident was in Simbach am Inn in southern Germany, where three women were found drowned in the basement of their house.
In the village of Julbach, a drowned woman was found hanging over a tree trunk in a stream.
Two people are also missing in the district of Rottal-Inn, with police saying they feared the worst.
On Wednesday, 20 members of a school trip on the Regen river had to be rescued.
Some residents on the border with Austria took to the roofs to escape the rising waters and had to be rescued by helicopter.
Floodwaters dragged cars, trees and furniture from flooded homes.
An emergency was declared in the historic town of Passau.
In Pfarrkirchen, more than 35 litres of water per square metre fell in the space of six hours on Wednesday.
School and road closures were also reported across the border in Austria.
In the district of Wesel, in North Rhine-Westphalia, a dam is threatening to break. Water levels are at 2m, 1.5m higher than normal, said a crisis centre official.
A landslip closed a rail line near Xanten, north-west of Duisburg.