Église Saint-Christophe de Cergy, Medieval church in Cergy, France

Église Saint-Christophe de Cergy is a church whose bell tower, one of the oldest in Val-d'Oise, has two levels of paired arched openings and a clock face. Its unfinished Renaissance portal, a carved relief panel framed by columns and a curved arch, faces the village. Inside, a square space three bays long and three bays wide is covered by one of the region's oldest ribbed vaults, with six historiated capitals of the 1130s–1140s.

Excavations in 2002 and 2003 revealed a small Merovingian burial chapel, 4 m wide with a flat chevet, replaced in the Carolingian period by a slightly larger chapel whose core survives in two eastern piers of the bell tower. In the second half of the 11th century a hemicycle apse was added, and the Romanesque church of the second quarter of the 12th century grew by successive enlargements. The Romanesque nave of the 1130s-1140s, dilapidated, was demolished in 1904, allowing the tower to be consolidated in 1905; the church was listed in 1913.

The church is dedicated to Saint Christopher, and its name recalls the former village of Cergy rather than the new town. Since two new parish churches opened in the ville nouvelle, Saint-Christophe has no longer been the parish's centre, yet at least two masses are still celebrated there each week. Look for the classified funeral and foundation plaques among the furnishings.

The church stands on rue de Neuville in the village quarter; its chevet faces the street directly, and a parking area lies to the east. The interior is entered from the courtyard formed by the unfinished north double-aisle walls, and the bell tower is best seen from that same courtyard. The unfinished Renaissance west facade is visible from the short dead-end lane west of the former cemetery, now a parvis.

Beneath the current building lie the remains of at least two earlier structures uncovered during archaeological excavations. These layers reveal how the site served as a religious center across different historical periods.