Marie-Élisabeth de Ludres was born in 1647 and was the daughter of Jean de Ludres and Claude de Salles. Isabelle (as she was called) became engaged to the Duke Charles IV de Lorraine in 1662 but the marriage never came to anything when the Duke married another noblewoman instead. Isabelle then attended the main court of France (she had been introduced to the Lorraine Court) where she served as a lady-in-waiting to the Queen Marie-Thérèse in 1670. Three years later she entered the service of Elizabeth Charlotte of the Palatinate as a lady-in-waiting.
Two years later in 1675 she attracted the notice of Louis XIV. But the King was not interested in making her an official maitrêsse-en-titre and made it clear to Isabelle that the relationship was to remain a secret. But Isabelle clearly did not listen to her royal lover and when she was heard publicly bragging that she would replace Madame de Montespan, Louis ended their relationship. Madame de Montespan had become so jealous about their affair that she started several rumours claiming that Isabelle had infected the King with venereal diseases that had left wounds on his body.
Isabelle left court (probably embarrassed by her failed attempt at becoming the King's mistress) and retired to a convent in 1678. After accepting a pension from the royal treasury she returned to Lorraine and was made a Marquise in 1720. Just six years later in 1726 Isabelle died.