The dog, known as Prince, attacked the four-year-old in the northern coastal town of Boulogne in July, leaving the girl with serious injuries to her forehead, eyes and ears. She also lost part of her nose in the attack.
The dog is now being held in solitary confinement and is due to be put down.
“We need to release this dog from hell,” Bardot told local newspaper La Voix du Nord. “He’s in total isolation; he sees no one.”
She acknowledged the attack had been “dreadful” and offered her sympathy to the young girl, although she expressed anger at parents who "leave children unsupervised with dogs."
Pleading for the dog to be spared she said, “this dog should be imprisoned for life" rather than be put down. "We have abolished the death penalty for humans, so why do we continue to apply it for animals?”
The mother of the four-year-old girl hit back at the former film star.
“It’s unacceptable,” she told radio station RMC on Monday. “She’s just there to defend the dog and she does not have the right to play down my daughter’s injuries. My daughter tells me every day that she looks like a monster.”
Bardot has been invited to visit the dog and see its living conditions by the deputy mayor of the seaside town. It is not yet known whether she will leave her Saint-Tropez home to visit the northern town at the other end of the country.
Bardot has been an animal rights campaigner for many years and set up her own animal protection foundation in 1986. She is frequently in the news in France for her outspoken views on immigration and has received several fines for inciting racial hatred.