The discovery in Saint-Quentin (Aisne) of two temporary brick kilns, in 2007 and 2009, prompted us to propose a detailed comparative analysis of the structures of these two unpublished industrial sites. The results of these two diagnostic reports of temporary brickworks are of undeniable interest for the understanding of the artisanal or «proto-industrial» process of firing bricks. The two brick kilns dating from the sixteenth to seventeenth centuries provide a lot of information both quantitative and qualitative for a more in-depth knowledge of these very singular cooking structures. The furnace on «La rue du Docteur Cordier» is of the «pit» type, rectangular in shape with natural fire reddened walls with two interrupted channels. This form is relatively well known at the beginning of the modern period, mainly in the north of France (regions Hauts-de-France and Île-de-France) and in the region Grand-Est. Pits with vertical walls, shallow depth and flat bottoms discovered near the furnace are probably basins/troughs for the preparation of the clay. The kiln on «l’îlot Pontoile» has a masonry enclosure with two side accesses. Its oven is defined on at least three sides by a thick brick masonry wall. Two phases have been identified with the addition of two walls reducing the space of the oven. It was originally equipped with four interrupted heating channels. Unlike the furnace on «La rue du Docteur Cordier» with its relatively numerous comparisons, the furnace on «l’îlot Pontoile», known as « masonry structure» has no equivalent in France in the sixteenth-seventeenth centuries. Finally, we propose a classification of brick kilns from the Middle Ages to the contemporary era. Traduction : John LYNCH