France and parts of the United Kingdom are gearing up for violent storms after a summer that saw weeks of drought and heat waves.

Fierce rainstorms hammered France overnight, flooding subway stations in Paris and causing traffic snarls as the French weather service on Wednesday warned of new flash flooding risks.

"The storms are making their way east... and can be violent with intense rain that in some places could see up to eight centimeters fall in a short amount of time," the Meteo France weather agency said.

On Tuesday, winds over 100kph (62mph) were reported at the top of the Eiffel Tower. Forecasts warned of similar winds on Wednesday in the southeast.

Weather warnings issued

Sudden storms saw Paris and other regions battered by hail.

In the south of France, rainstorms flooded the Old Port of Marseille and the city's main courthouse and led to the closure of nearby beaches.

Alert levels were announced for 13 departments, which included several along the Mediterranean coast and surrounding the southeastern city of Lyon.

Weather warnings were also issued for Normandy along the English Channel in the northwest, extending toward the border with Belgium.

Authorities called on people to postpone travel plans and to avoid waterways.

"Just 30 centimeters of water is enough to sweep away a car," the prefecture of the Var department on the French Riviera said in a statement.

The recent rainfall has offered some respite to firefighters battling France's worst fire season in the last decade.

Scattered wildfires, however, continue to burn in southwest France, authorities.

Most parts of Western Europe have experienced a season of extreme weather that experts link to human-made climate change.

London and other parts of southern England witnessed flash flooding as torrential rain and thunderstorms whipped the country that recorded its first ever 40 degree Celsius temperature last month.

But despite the downpour, much of England is officially still in drought after one of its driest summers.