This explains a lot about the above-mentioned abbés who feature prominently in The Count of Monte Cristo.
The French title answering to Eng. abbot, but extended to ‘every one who wears an ecclesiastical dress,’ Littré; and specially applied to one having no assigned ecclesiastical duty, but acting as a professor, private tutor, or master of a household; in which sense the word is simply transferred into Eng. instead of being translated. Thus, ‘Anselm, abbot of Bec,’ ‘the Abbé Montmorency.’ Cf. Ital. ABBATE.