Paris has been on flood alert for the last two days, with the Seine bursting its banks and swamping riverside highways, causing all river traffic, including the popular "bateaux-mouches" tourist cruises, to be suspended.
French Prime Minister Manuel Valls said on Thursday the government expected great difficulties in some areas in the coming hours.
"We are still very worried," he told reporters at a crisis room in the French capital.
On Wednesday, an 86-year-old woman was found dead in her flooded home in Souppes-sur-Loing, about 85 miles south of the French capital, the interior ministry said. Floods have also killed at least four people in neighbouring Germany.
In Paris, officials said the Seine was set to rise to a peak level of 5.60 metres on Friday, below the 6.00 metre level at which the underground RER railway would be flooded and far below the 8.60 metre record hit in 1910.
The national weather service said the greater Paris region had in May endured its wettest month since 1960.
In the Loiret region, were the local prefect mobilised the army to help evacuate motorists trapped on the A10 motorway, the floods are the most severe in 100 years.