She was, moreover, anxious to limit the power of the Comte de Soissons, and to prevent the proposed marriage of his son Louis de Bourbon with the heiress of Montpensier, which would have opened up a still wider field for his ambition.  She accordingly espoused the cause of the Duc de Guise, who, having no other alternative by which to rid himself of the Marquise, did not scruple to deny the authenticity of the signature ascribed to him; and he had no sooner resolutely done this, than the Regent placed the affair in the hands of the President Jeannin, who with his usual ability at length succeeded in inducing Madame de Verneuil to withdraw her claims.  Aware that he could hope nothing either from her generosity or her dread of ridicule, the astute lawyer represented to her the inequality of the contest in which she was about to engage without any ulterior support; whereas the Duc de Guise was not only powerful in himself, but would necessarily be supported by all the members of his family, as well as protected by the Queen.

The Marquise for a time affected to believe that the legality of the document in her possession must enable her to triumph even over these obstacles, formidable as they were; but Jeannin reminded her of the death of one of her witnesses, the denial of another, and the solemn declaration of the Duke that his own signature was feigned; assuring her that these circumstances must prove more than sufficient to prevent the recognition of the deed in any court of law.  When he found that this argument had produced the desired impression, he next proceeded to expatiate upon the benefit which she could not fail to derive from the gratitude of the Guises, should she voluntarily withdraw her claim without subjecting the Duke to the annoyance of a public lawsuit; during which, moreover, her former liaison with his brother, the Prince de Joinville, could not fail to be made matter of comment and curiosity.  He urged upon her the desirability of avoiding a publicity which must tend to dishonour both herself and her children; and, finally, he pointed out the propriety and policy of seizing so favourable an opportunity to secure the goodwill of the Regent, who would as a natural consequence be gratified by such a concession, and be thus induced to bury the past in oblivion.

Madame de Verneuil wept and argued in vain.  Jeannin was indeed too subtle an antagonist to afford her one inch of vantage-ground; and he so thoroughly undermined the reasonings which she advanced, that, wearied and discouraged, she at length consented to forego her claim.

Deprived of the position which she had formerly held at the Court, she never re-appeared there, but spent the remainder of her life either on her estate at Verneuil, or in her hotel at Paris, in such complete retirement that nothing more is known of her save the period of her death, which took place on the 9th of February 1633, when she had reached her fifty-fourth year.[72]