He appeared in Sharpe's Enemy and met Richard Sharpe when both men arrived at the Gateway of God convent to deliver ransoms for hostages being held by the army of deserters led by Pot-au-Feu and Obediah Hakeswill. His English born wife, Sarah, was among the hostages, and it was she who gave them the clue they needed to know where the hostages were being held.
During the necessary truce between Sharpe and Dubreton, they developed a regard and respect for one another. He observed the hatred between Hakeswill and Sharpe, and when the deserters were routed and scattered, he delivered the fugitive Hakeswell to Sharpe with his compliments.
During a Christmas dinner for both British and French officers under truce, Teresa arrives but would not enter the inn while the hated French were within. Dubreton came outside and Sharpe introduced him to Teresa who he knew only by her terrifying reputation, "You are as beautiful as you are dangerous, ma'am." To Sharpe's surprise Teresa was polite to him, and he said that to be her friend it might be worth losing the war. She was pleased with the compliment and allowed Dubreton to kiss her hand to her husband's complete astonishment.In the aftermath of the battle at the Gateway, he witnessed Hakeswill's escape and subsequently his killing Teresa.
He returned the fugitive to Sharpe, and told him what he'd seen.
Prior to the war, he attended the Royal Academy of Equitation in Angers, France with Arthur Wellesley.