A reaction occurred between the electricity from the racquet and the flammable gas in his home, causing a large explosion, which destroyed part of his kitchen and brought down a section of the ceiling.
The octogenarian, from the village of Parcoul-Chenaud in Dordogne, remarkably managed to escape with only a burn to his hand. He was taken to Libourne hospital for checks.
A local investigator told the Daily Mail: "On this occasion, gas was leaking into the man's house. The very hot zapper ignited the gas, causing a sudden explosion."
"The man was lucky to get away with a burned hand after diving on the floor, but the kitchen was destroyed along with part of the roof."
He has since checked in to a local campsite while his family conduct the necessary repairs to his home, local news outlet Sud Ouest reported.
Electric fly swatters are usually harmless to humans, sending out only a small shock, but there are documented incidents of people suffering burns.
The fly's fate remains unknown.