Mezni began her career in banking before cofounding the SAH Group alongside Mounir El Jaiez in 1994. The group’s subsidiaries include SAH Tunisie, SAH Algéri, SAH Côte d'Ivoire, and SAH Libye, among others. In the first nine months of 2024, the group recorded revenues of $240 million, with SAH Tunisia contributing up to 48.7% of overall sales, followed by Azur Détergent and Azur Papier, with 17.4% and 10.2%, respectively.