He set up a conspiracy with his cousin Gaston d'Orléans (future husband of the duchess of Montpensier and younger brother of Louis XIII) and the comte de Montrésor with the intention to murder Cardinal Richelieu and depose the King, but the plot failed (1636).
Ia bersekutu dengan sepupunya Gaston d'Orléans (calon suami duchesse de Montpensier dan adik laki-laki Louis XIII) dan Comte Montrésor untuk membunuh Kardinal Richelieu dan menggulingkan Raja, namun rencana tersebut gagal (1636).