The Basilica of Notre-Dame is the most striking building in Alençon's old quarter. The original church was built in the 14th and 15th centuries in the Flamboyant Gothic style, with an elaborate porch added in the 16th century. The three porches on the west front are covered in intricate stone carving — faces, foliage, and Biblical scenes — that repays close examination.
Inside, the nave is tall and light, with good stained glass dating from various periods. The church was given the status of a minor basilica in 1959 in recognition of its connection to the family of Sainte Thérèse of Lisieux, who was born in the town. A side chapel is dedicated to the Martin family. Entry is free.