Persons sentenced to a custodial sentence for one or more of the offences mentioned in articles 221-3,221-4,222-3,222-8,222-10,222-12,222-14-1,222-14-5and 222-15-1 of the Penal Code to the detriment of a person invested with a public elective mandate, a magistrate, a member of the national gendarmerie, a member of the military deployed on national territory as part of the requisitions provided for in article L. 1321-1 du code de la défense, an official of the national police, customs or prison administration, a municipal police officer, a professional or volunteer fireman or any other person holding public authority may not benefit from the reductions in sentence mentioned in article 721 of this code only up to, in the case of a felony, three months per year of incarceration and seven days per month for a period of incarceration of less than one year or, in the case of a misdemeanour, four months per year of incarceration and nine days per month for a period of incarceration of less than one year.