Firefighters were called to the Golden Star chocolate shop on Rue Fontaine in the 9th arrondissement of the capital at around 4pm.
The blast which occured in a part of the shop that was under construction caused considerable damage, as seen in the photo below, and left five injured, one seriously.
It is believed the wounded were all construction workers.
According to reports in the French press work was being carried out in the basement of the store to fix a gas pipe, when the blast occured.
"It could be a gas explosion but at the moment nothing is sure," a source close to the investigation told Europe1 radio.
One witness who worked across the road from the Golden Star told Europe1: "I saw the window blow out. It was shocking.
"It's lucky no one was passing infront. The wounded were taken to the nearby brasserie to be treated," he said.
Paris mayor Bertrand Delanoë sent a message of support to the victims.
The aftermath was caught on camera by witness Mathieu Ott.
Explosion (?) de la chocolaterie rue fontaine, Ooh! pic.twitter.com/mKClly6bty
— Mathieu Ott (@Mathieuott) February 14, 2014