Born in Lorient, France, Duminy was an illegitimate child.Birth 1747 in AD56 () According to French naval records, his father was Antoine Duminy, a long-serving member of the French army (born in Tarascon as Antoine Lebre, he adopted the surname Duminy as a nom-de-guerre, became commander of the citadel of Port-Louis, Morbihan and died in Bayonne in 1768 while commanding the citadel there). According to one document, his mother was Anne le Goff, about whom nothing is known.
