It is the neatest part and most remarkable. It dates from XIIIth century. It is the place where the community meet, where the abbot exerted his magistery and where he pointed out the chapters of the rule.
The rectangular space of 12,64 m out of 8,48 m is organized in two naves forming six square spans arched on intersecting ribs, whose repercussions are supported in the medium by two piles cut in facets multiple and surmounted capitals decorated with water sheets, broad and punts. The room opens on the cloister by a flanked central arcade of two arcades geminated on sideboard.