 In Bay 9 of the north side of the ambulatory is this window attributed to Lavergne.In the centre of the window two panels recall the history of the dogma surrounding the concept of the Immaculate Conception whilst around this several panels celebrate the sanctuaries in Lėon and Trėgor devoted to the Virgin Mary.One panel recalls Notre-Dame de Berven, and others Notre-Dame de Kreisker, Notre-Dame auxiliatrice at Lesneven, Notre-Dame du Mur, Notre-Dame du Folgoët and Notre-Dame de Kernitron.