Église de l'Immaculée-Conception de Lyon, Byzantine Revival church in 3rd arrondissement of Lyon, France.

Église de l'Immaculée-Conception is a neo-Byzantine church built from 1856 by Pierre Bossan, with a fortified exterior of light gray ashlar and a rose window beneath the tower's louvered openings. Inside, a 30 m nave and 17.50 m width lead to a domed choir on a near 40 m square, with pale stone columns, round arches, and a barrel-vaulted ceiling.

The parish was created by imperial decree in 1855, the first in France named for the Immaculate Conception dogma proclaimed on 8 December 1854. Priest Auguste Coudour began the church in 1856 to plans by Pierre Bossan, with William Léo supervising; the nave and crypt were finished in 1859 and partly consecrated by Cardinal de Bonald. Work on the domed choir and chapel ring stalled, then Charles-Marie Franchet completed it from 1892 to 1897, when Cardinal Coullié consecrated the church.

The church is nicknamed "Immac" locally. Its north choir chapel is dedicated to Saint Jude Thaddeus and its walls are covered with votive plaques thanking the saint, invoked in hopeless situations. The south chapel holds a Marian statue by Joseph-Hugues Fabisch, and the east chapel was painted from 1913 to 1920 by Bruno Guillermin.

The church stands between Rue Pierre Corneille to the west and Avenue du Maréchal-de-Saxe to the east, next to the 19th-century Hôtel de préfecture du Rhône; it belongs to the parish of Saint-Pothin. The nave is 30 m long and 17.50 m wide, and the dome choir forms a square of nearly 40 by 40 m. Look for the north choir chapel of Judas Thaddäus, its walls covered with votive tablets.

The building used innovative construction techniques of its time to support the weight of the vaults with groups of thin columns. This clever support system allowed for a wide open interior space beneath the dome.