Notre-Dame Church is a Catholic parish church located in Vetheuil, in Val-d'Oise. By its size, its double side plan and its particularly rich and varied furniture, it stands out from the village churches of French Vexin, because Vétheuil was a town of some importance in the Middle Ages. By its architecture, and in particular its apse of primitive Gothic style and its two Renaissance portals, the Notre-Dame church occupies a special place among the religious architecture of religion. Its heritage value was recognized early on, and it was classified as a historic monument by the 1840 list [2]. The origins of the parish and the church are not known, but we know of a first mention of the end of the eleventh century, and remains of a Romanesque steeple from the first half of the twelfth century still remain inside the current bell tower. Towards the end of the twelfth century, the construction of a new choir was launched, and it was completed at the very beginning of the thirteenth century. The bell tower was rebuilt in the Gothic style during the same century. It is impossible to comment on the nave of this period. The western parts that we see today date exclusively from the first half of the sixteenth century, and are in the Flamboyant Gothic style. The narrowness of the vessel is controlled by the distance between the stacks of the bell tower, and may also be explained by the reuse of the foundations of the old nave. The narrowness is compensated by the addition of wide and high side aisles, and a row of chapels forming a second side aisle on each side. In 1551, the local lord called on the master mason of Italian origin Jean Grappin, who erected a sumptuous southern portal protected by a porch, then a western facade flanked by two turrets. These works evoke the Italian Renaissance, and are of exceptional quality. Unlike other religious monuments in the region, the Notre-Dame church has always benefited from the restoration and maintenance work necessary for its good conservation, and it is in good condition. Vétheuil is no longer an independent parish and no longer has a resident priest, but Sunday Masses are still celebrated in the Notre-Dame church about every other Sunday.