"It was quite moving," the mayor, Jean-Robert Gachet, told news agency AFP.
On Saturday morning, the bride, who was unnamed in the French press, almost cancelled her wedding.
Heavily pregnant, she started feeling unwell. But with the July 14th due date still a week away, she decided to go ahead with the 11am ceremony.
At the town hall, the mayor noticed that the bride was looking a bit tired.
"I thought it was the stress of the wedding, so I decided to hurry through the vows," he said.
During a photo session on the steps of the town hall, the bride felt the wedding butterflies in her belly give way to something larger. Relatives called the emergency services while the bride was moved back inside.
By the time the firemen arrived, the bride’s waters had broken and she gave birth to a baby boy in the town hall.
"The first cry of a newborn baby in the town hall, it was so moving. It was a first for us and a first for the fire brigade," said Gachet.
Her son, Jarod, is reported to be in good health.