MACLOVIENSIS (Saint-Malo - Côtes-d'Armor)Created about 1160 by the transfer of the See of Alet (today Saint-Servan).
MAGALONENSIS (Maguelonne - Hérault)Created in the sixth century, transferred in the eighth to Substantion (today Castelnau-le-Lez) then to Villeneuve (Villeneuve-lez-Maguelonne). Reinstalled at Maguelonne about the middle of the eleventh century, then transferred in 1536 to Montpellier.
MALLEACENSIS (Maillezais - Vendée)Created on the 13 August 1317 by dividing the See of Poitiers.
MASSILIENSIS (Marseille - Bouches-du-Rhône)Mentioned in the fourth century.
MATISCONENSIS (Mâcon - Sâone-et-Loire)Created in the fifth century.
MAURIANENSIS (Maurienne - Savoie)Created in the sixth century.
MELDENSIS (Meaux - Seine-et-Marne)Created in the fourth century.
METENSIS (Metz - Moselle)Created in the third century.
MIMATENSIS (Mende - Lozère)Created about the middle of of the tenth century by transferringthe See of Javols.
MIRAPISCENSIS (Mirepoix - Ariège)Created by the division of the See of Pamiers 27 September 1317.
MONTISALBANI (Montauban - Tarn-et-Garonne)Created on the 25 June 1317 by dividing the See of Toulouse.
MORINENSIS (Thérouanne - Pas-de-Calais)Mentioned in the eighth century. Transferred in the ninth and tenth centuries to Boulogne, then a double residence with its seat at Thérouanne.