Église Saint-Cœur-de-Marie de Concarneau, Catholic church in Concarneau, France.

Église Saint-Cœur-de-Marie de Concarneau is a church with eclectic architectural elements located in the coastal town of Concarneau. Its unfinished bell tower and remaining structural details reflect influences from Byzantine tradition and Western religious architecture.

Begun in 1912 to plans by diocesan architect Charles Chaussepied, who drew on Hagia Sophia and Saint-Front de Périgueux, the church was halted by World War I and slowed by ground problems. It was blessed on 17 March 1929, still unfinished, and the transept chapels meant to support the dome were never built. After the October 1987 storm it was closed, then demolished with a wrecking ball in 1994-1995.

The church was the only one in Finistère dedicated to the Immaculate Heart of Mary and the only one there in Romano-Byzantine style. In 1951 Jean-Marie Martin and André Even painted 300 m² of interior decoration on the theme of the Life of Mary, the Nativity and the Entombment; these works were destroyed with the building.

The bell tower stands on the site of the former church, now occupied by the Saint-Guénolé church inaugurated in 1996, so the two are seen together. The tower is viewed from the surrounding streets; the preserved capitals kept at the request of Louis-Pierre Le Maître and the Société archéologique du Finistère are not part of the standing structure.

The tower and capitals survived only because Louis-Pierre Le Maître and the Société archéologique du Finistère asked for them to be kept as "witnesses of the past". The rest of the church came down "à la boule" in 1994-1995, and a contemporary church dedicated to Saint Guénolé was inaugurated on the site in 1996.