In 1740, she opened a fashion shop at the Rue de la Monnaie in Paris.
She had a successful career and reportedly supplied fashion products to the aristocracy for forty years.
During the last years of Louis XV, Alexandre was described as the top fashion merchant in Paris alongside Le sieur Beaulard, and Sébastien Mercier in Tableau de Paris described her and Beulard and the two rulers of fashion.
Her fame gave her international clients, and she was able to import and export her fashion products.
She had clients within the ladies-in-waitings of the royal court, and was given the assignment of providing the French wardrobes of the princesses Marie Joséphine of Savoy and Maria Theresa of Savoy when they married into the royal house in 1771 and 1773.