The 59-year-old man was found on Friday morning in his car near the town of Epineuil-le-Fleuriel, in the Cher department of central France. The area had been hit by heavy rain throughout Thursday evening.
His submerged body was discovered by firefighters around 8am. His car had been swept away and flipped over by the Queugne river that had broken its banks.
It is believed he had popped out to pick up his bread as he did every morning in Epineuil-le-Fleuriel. The local gendarmerie said the river's water had risen quickly due to downpours upstream.
The latest death comes after a 37-year-old man was found drowned in his car in northern France on Tuesday.
On Wednesday a woman in her nineties died in Montmorillon, a town in central-western France, probably suffering a heart attack while trying to mop up the water in her flooded home.
(This was the scene at Chapponay near Lyon on Friday. AFP)
Meanwhile the body of a woman in her eighties was found in a river in the Lot-et-Garonne region of southern France where heavy rain had fallen overnight, police said.
Meteo France estimated the number of lightning strikes in May at 182,000 nationwide, almost double the record figure for the same month previously set in 2009.
The small town of Morlaix in northwestern Brittany was still counting the cost after being submerged on Sunday night when an estimated month's worth of rain fell within half an hour.
Heavy rain, lightning and sometimes hail have hit wine-growing areas in the Bordeaux, Cognac and Champagne regions over recent weeks, causing major damage to crops.
Storms have also disrupted play at the Roland Garros tennis tournament in Paris.