Paris is on alert as floodwaters continue to rise with the River Seine at six metres above its normal level.
The flood has forced parts of the of the metro systems and major landmarks to close, and the Louvre and Orsay museums have been shut while staff moved artworks to safety.
Environment Minister Segolene Royal said floodwaters had submerged riverside roads and swamped small businesses on quaysides.
The Seine is set to reach as high as 6.5m and, with more downpours forecast, is unlikely to recede over the weekend.
At least 15 people have died across central Europe as heavy rainfall caused flooding from France to Ukraine.
Ten poeople were 10 were killed in southern Germany as several towns were devastated.
Two people died in France, two fatalities were reported in Romania and one in Belgium. Austria, the Netherlands and Poland have also been affected.
Tens of thousands of people have been forced from their homes.
At the Louvre, curators scrambled to move 250,000 artworks to higher ground from basement storage areas at risk of inundation from what President Francoise Hollande called "exceptional flooding".
In Paris, the Cluny - La Sorbonne and St Michel metro stations were closed as a precaution while the river spilled onto the city's streets.
Bridges were closed and non-emergency boats were banned from the Seine as its swelling forced the closure of museums, parks and cemeteries.
French authorities have even taken initial steps to transfer the presidency and key ministries to secure areas, AP news agency reported.
The worst affected areas lay just to the south of the capital. In Villeneuve-Saint-Georges near Orly airport, soldiers and Red Cross volunteers helped stranded residents as flood waters rose above knee level. In nearby Corbeil-Essonnes, locals kayaked along streets littered with abandoned cars.
"It's a bit frightening, everything that's happening," said one woman from Marseille who identified herself only as Odile. "Not long ago they ran a flood simulation, how to evacuate museums, residents. And now it's happening for real."
The heavy flooding of the past week could cost French insurance companies some 600 million euros ($680.5 million) or more, industry association AFA said.
France's rainfall levels in May were the highest since 1873, but the crisis is eclipsed by the 1910 floods that saw Paris submerged for two months.
The river level peaked at 8.62m that year, and has since reached 7.1m in 1955 and 6.18m in 1982.
-BBC / Reuters