Swollen by weeks of heavy rains, the Seine River is expected to reach its peak in the French capital late Sunday or early Monday.
Paris regional authorities say the floods have already caused damage in 240 towns. In Villennes-sur-Seine west of Paris, the ground floor of some buildings has disappeared underwater and residents are using boats instead of cars.
In Paris, cruise boat companies are suffering losses because all river traffic has been banned for days.
Police fined people who took a canoe Saturday into the Seine in central Paris, and sternly ordered others in a tweet against such actions, calling them "totally irresponsible."