From The Law of Treason and Treason Trials in Later Medieval France, concerning the rough handling the king deployed in an attempt to squelch the Breton War of Succession:
Not long after the executon of Olivier de Clisson a group of Breton nobles attacked Charles de Blois as he was on his way to Paris. Fourteen — among them the two Geoffroys de Malestroit, father and son, Alain de Cadillac, Jean de Montaubon, Fulk de Laval and Henri d’Avaugour — were captured and taken to Paris. Although Philippe VI formally turned the case over to the Parlement, he made sure that the court did as he wished. On 24 November 1343 he advised it that he was sending the prevot of Paris and Jean Richer, maitre de requetes de l’hotel, ‘for certain matters regarding the Breton prisoners. We instruct you accordingly,’ the king cautioned, ‘that you accept what they have to say on our behalf.’
On 29 November the accused appeared in the Parlement, confessed to their treason and were then sent back to the Chatelet without the court having passed sentence. In fact the decision in this case was taken away from the Parlement by the king. On that same day Philippe VI ordered the prevot of Paris to execute the prisoners forthwith, ‘because we condemn them as traitors’. Philippe’s determination in this matter was patent. In concluding his instructions he wrote: ‘take care that there is no slip-up if you do not want to incur our wrath’. Except for Laval and Avaugour, the Bretons were drawn and beheaded that same day; and their corpses were then drawn to the gibbet to be hanged there. These executions had the desired effect on at least some of Montfort‘s partisans: Jean, eldest son of the count of Vendome, for example, quickly made his peace with Philippe VI.