Part of the city hall is visible, it occupies what was once part of the abbey, adjoining the north side of the church (converted 1790-1800).

The church was originally built as the abbey church of Saint Ouen for the Benedictine Order, beginning in 1318 and interrupted by the Hundred Years' War and sacked and badly damaged during the Harelle. It was completed in the 15th century in the Flamboyant style. The central crossing is surmounted by an unusual lantern-style tower (1441) similar to that at Ely Cathedral in England. The gradual and complex transition from Rayonnant to Flamboyant in the architecture of Rouen in the late 14th century and the early 15th is seen in the varied styles of the transept. The well-preserved stained glass is predominantly from the 14th century. In the 19th century (1846-1851) the incomplete façade was demolished and replaced by a 14th-century Gothic Revival design by Henri-Charles-Martin Grégoire.