French Prime Minister Jean Castex is due to visit the southwestern Lot-et-Garonne department on Friday following serious flooding in recent days in the wake of Storm Justine.
The level of the River Garonne around Marmande -- between Bordeaux and Toulouse -- remains "very high", although the red alert was reduced to orange on Thursday.
The head of the government is to see rescue operations in progress and meet local government and other officials.
The Garonne reached a height of 10.20 metres overnight from Wednesday into Thursday, a level not seen for 40 years and just short of the record, set at 11.39m in June 1875.
The two bridges over the river at Marmande remain closed. The nearby town Meilhan-sur-Garonne was left underwater. In the wider region scores of people had to be evacuated.
According to the authorities, emergency crews have intervened more than 300 times to deal with endangered property, fallen trees, and to rescue people, since Storm Justine struck last weekend, bringing flooding in its wake.
On Thursday morning 45 roads remained closed in Lot-et-Garonne, 12 were underwater and six schools were still closed.
Paris was put on flood alert earlier this week with the River Seine's water levels on the rise following heavy spells of rain.