Johnny Stark left behind a legal "bloody mess." It took Mathieu and her lawyers years to close out and process his estate. "I was severely depressed, but I got out without needing analysis." The most controversial event of Mathieu's career, according to the media of the time, occurred when she took over Stark's office, and ended her business relationship with Nadine Joubert. She lost confidence in Nadine who tried to modernize her act after Mathieu's "l'Américain" album failed miserably, with the strain of Stark's legal affairs having set her back financially. Her sister Monique stepped in to become her business manager, and the two women have remained profitable in the industry ever since.