In 1675, Isabelle became involved in a relationship with King Louis XIV. Louis wished the relationship to be secret and had no plans to make her official favorite, and when she openly declared that she was going to replace Madame de Montespan the relationship was ended by Louis. Ludres left the court in 1678 and moved to a convent in Paris. She eventually accepted a royal pension and move back to Lorraine. She was made marquise in 1720.