The church Saint-Denis consists of two very distinct parts, namely a fairly spacious Romanesque nave of the late eleventh century, and a homogeneous set of the sixteenth century transept, central bell tower above the crossing of the transept, choir of two bays at the apse with cut sides and two side chapels of the choir, carrying on two bays each. The braces have large gables common with the surrounding chapels, while the eastern chapels have independent gables, also overlooking the north and south.
The nave is devoid of buttresses. Because it is wider than the transept square, it could be directly connected to the transept arms by narrow passages. The ceiling is vaulted in wooden cradle, and the walls are perfectly bare inside. However, three narrow semicircular windows from the late 11th century remain to the north. Their counterparts to the south have been blocked and remain visible only from the outside. With this exception, the Romanesque character of the building was lost as a result of successive alterations. For example, there is no longer a Romanesque portal. The western portal is in a basket handle and surmounted by a modern semicircular bay; the northern portal is in a third point. An octagonal stair turret occupies the corner between the north wall and the north crosspiece.
The structure of the nine bays of the sixteenth century belongs to Gothic art, and the interior decoration evolves from the flamboyant style to the Renaissance style to the south, but all the bays are however in third point, which is also the case of the bell tower openings. The bays are vaulted on crossed ogives whose ribs fall on lamp ends to the north and on consoles to the south, while they are penetrating in the central vessel, that is to say they merge in the pillars. A vault, however, that of the south-west chapel next to the south cross, corresponds to the Renaissance gôut, and its center is occupied by a square in which the ribs intersect. At the five meeting points, medallions were placed.
The windows are filled in flamboyant style with regard to the three bays of the north and the chevet, and Renaissance style with regard to the three bays of the south. The bedside also has only one bay, the walls placed at the sides being blind. Buttresses support the walls at the ends and at the boundary between two spans. At the four ends, there is only one buttress placed at an angle, which already indicates the transition to the Renaissance. The buttresses of the north and south facades end in pinnacles, with the exception of those in the center of the large gable walls, which continue beyond the pinnacles to the tops of the walls. The foothills of the chevet end in a glacis. The bell tower has only one floor of low height, openwork on each face of a bay in third-point with a blazing repolage. The roof is two-rumped.