The church is closely inserted between the castle park and the houses of the village, which presents a harmonious ensemble of buildings from the 18th and early 19th centuries, combining flint and brick with lime plaster tinted with ochre. You have to step back a little to see its apse, the foundation of which probably dates back to the Romanesque period. Next to the entrance gable, dressed in Grison rubble, the bell tower was built in 1867 (according to the inscription preserving the names of the mason Gelin and the carpenter Hallier, with those of the priest, Abbot Porcher, the mayor, Viscount des Brosses, and the municipal councilors). The nave is extended by a rounded apse, with thick walls pierced by widely splayed semicircular openings, between which are placed the statues of Saint Sebastian, the Virgin and Child, Saint Michael and the dragon, and a holy bishop. On the "perque" (or beam of glory), a large Christ surrounded by the Virgin and Saint John. The transverse chapel, on the right, from the 15th or 16th century, vaulted with ribs resting on four pendentives with a central key carved like lace, was the seat of the brotherhoods. It houses the more recent statues of Saint Sebastian, the Virgin, Saint Michael and a holy bishop. The seigneury of Chennebrun, which belonged successively to Saint-Simon de Courtomer (1650), Caumont de la Force (1670), Grimoard de Beauvoir (1688), Laval Montmorency (1714), d'Espinay Saint-Luc (1765), etc., was acquired during the Restoration by Jacques-Alexandre Giroult des Brosses, whose father had been mayor of Dreux in 1771. In the seigneurial chapel on the left, inscriptions recall the names and dates of the members of this family linked for more than four generations to the life of the commune. We are grateful to them for having admirably maintained the castle, whose 18th century façade and the entrance to the park are visible from the gate. Their coat of arms appears on the stained glass window of this chapel, where we recognize in the center those of a Laval-Montmorency, Lord of Chennebrun, knight of honor of the Duchess of Orléans, master of the cavalry camp, who died in 1757, as indicated by his funerary slab on the threshold. The numerous 19th century stained glass windows with the names of the donors are worth seeing in detail. The one in the center, in the choir, lifts us to the sky with Our Lady of the Assumption. The statue of Mary, patron saint of Chennebrun, never ceases to watch over her church.