The current building is the third built on the site. A first chapel, already dedicated to Saint Nicolas, patron saint of merchants, was erected during the 12th century. It became a parish in 1224. A second church was built and completed in 1449 but it was destroyed, with the exception of the tower, during a fire in 1664. The current church was built around 1701 according to the plans by architect Vincent Anthony2. The facade underwent a major restoration from 2011 until November 20153.
The facade and interior decoration are in Baroque style. The building is mainly high in brick with a decorative addition of limestone at the angles and bands. The building, about 88 ¡m long and about 30 meters wide, has three naves of five bays, a transept and a three-bay apse completed by adjacent chapels. A few steps and a ramp provide access to the entrance gate.
The square tower, placed completely forward and to the left of the rest of the facade, has a Bray sandstone base and has five brick levels surmounted by an octagonal spire.
The facade is made up of two distinct parts and of different heights topped by pediments with curved lines specific to Baroque architecture. On the left part, the large limestone portal forms a semicircular arch surmounted by a niche and surrounded by semicircular pilasters4.
Inside, the choir and high altar in Baroque style are remarkable. The church also houses the statue of Our Lady of Montserrat which came out during the procession of the Ducasse de Mons. Above the entrance gate, a glass slat glass roof was created in 2013 by master glassmaker Bernard Tirtiaux. 6.5 m high and 4.5 m wide, it represents a stylized blue bird