Notre-Dame aux Rouges is the name of the statue of the Virgin Mary that stood in the chapel founded by Saint-Géry. It was long venerated by residents, who invoked Mary's assistance in warding off scarlet fever (hence, the name), which was endemic in the swampy terrain. The image was first carried in procession through nearby streets on 25 August 1538. In 1798, when the church of Saint-Géry was demolished, the venerated statue was moved to Notre-Dame de Bon Secours.
Historical Dictionary of Brussels. Paul F. State.