Despite its apparent unity, the Gothic church that can be seen today is in fact the result of numerous make-overs stretching back to the Middele Ages (14th century) and up to the last city enlargement in 1868.
Its five naves, all of the same height, and its tower in the façade make it an example of an "Hallekerque", one of the barnlike churches whose light structure was particularly adapted to the fragile, and often marshy, soil of Flanders. Under the French Revolution it became a "Temple of Reason". The interior is adorned with numerous paintings by Lille artists dating from the 17th and 18th centuries. The central chapel is dedicated to Sainte-Barbe, patroness of the Lille artillerymen who defended the town repeatedly from 1485 onwards and whose story is told in a museum not far away.