METEO France has issued an "orange" weather alert - the second highest level out of four - for the Pas-de-Calais department in the north of France.
The weather forecasting body said water levels along three rivers - the Hem, Aa and Liane - were dangerously high after heavy rainfall earlier this week.
Traffic conditions could be difficult today and power cuts are possible. The weather warning is in place until 6am tomorrow.
There are no reported delays or cancellations on the cross-Channel ferry services.