Train services have been disrupted and soldiers are preparing to assist as rivers across France continue to swell following heavy rain.
Meteo France, the national weather agency, said 23 departments remain on orange alert, the second highest level of vigilance, and urged people to limit their journeys and to be on the alert.
The weather has improved in large parts of the country, but more rain is expected on Thursday.
Police forces and the fire brigade are already on site, patrolling flooded streets on small boats.
Ms Altman told France Info radio that water levels are expected to keep rising until Friday.
“We should get military trucks to help us evacuate and make people move along,” she said.
Forecasters said the Seine levels should keep rising until the weekend. The river is expected to reach a peak last reached in June 2016, when authorities were forced to close several Parisian monuments including the Louvre museum.
Roads along the shores of the Seine remained closed on Wednesday as well as seven train stations alongside the river.