Named after the Franciscan Sisters of Mercy, whose motherhouse is in Belair.
The congregation goes back to Elisabeth Dufaing, remembered as 'Mother Franziska', in the mid-19th century. The sisters ran two clinics on the Fish Market in the old town, Saint-François and Saint-Joseph. In 1919–1921 they built their convent in Belair, and in 1921 their motherhouse moved here.