One of his first acts after entering on the duties of his office was to cause the parlement of Paris to register the edict of Romorantin, of which he is sometimes, but erroneously, said to have been the author.
The duke of Guise was now named lieutenant-general of the kingdom, but his Catholic leanings were somewhat held in check by the chancellor Michel de l'Hopital, through whose mediation the edict of Romorantin, providing that all cases of heresy should be decided by the bishops, was passed in May 1560, in opposition to a proposal to introduce the Inquisition.
Seven years before he had started a model farm at Frechine, where he demonstrated the advantages of scientific methods of cultivation and of the introduction of good breeds of cattle and sheep. Chosen a member of the provincial assembly of Orleans in 1787, he busied himself with plans for the improvement of the social and economic conditions of the community by means of savings banks, insurance societies, canals, workhouses, &c.; and he showed the sincerity of his philanthropical work by advancing money out of his own pocket, without interest, to the towns of Blois and Romorantin, for the purchase of barley during the famine of 1788.
Despite the edict of Romorantin, which by giving the bishops the right, of cognizance of heresy prevented the introduction of the Inquisition on the Spanish model into France; despite the assembly of Fontainebleau, where an attempt was made at a compromise acceptable to both Catholics and moderate Calvinists; the reform party and its Bourbon leaders, arrested at the states-general of Orleans, were in danger of their lives.