It was Father François who initiated the construction of the upper part of the monument, and the architect Adrien Boisson who designed the pedestal. It is composed of two pyramidal walls arranged diagonally and forming three floors. The first floor (the lower one) has blind arches, but the two upper floors have Neo-Gothic arcades. At the intersection of the two walls is a central shaft supporting the pedestal of the Virgin. The pedestal is very richly decorated: small columns, rose windows, trefoil arches, and small towers. Statues are placed at the edges of the different floors:
1st floor: the Saints: Saint Joseph, Saint John, Saint Bernard, and Saint Vincent;
2nd floor: the Saints: Saint Anne, Saint Elizabeth, Saint Madeleine, and Saint Theresa.
On the third floor, angels have been sculpted. The architect Boisson thus intended to symbolize the prayer that springs from the earth to heaven, then is transmitted by the saints, men and women, and finally by the angels to the Virgin Mary. The statue of the Virgin Mary at the summit is 3.50 m high. It is said that she watches over the serenity and tranquility of the city.
Once the construction of the pedestal was completed, the building was inaugurated on May 3, 1863 (six months after its purchase) by the Bishop of Valence, in the presence of Father Gabriel of the Abbey of Notre-Dame d'Aiguebelle, forty priests, and 15,000 faithful. The first mass at the Notre-Dame de Bon Secours chapel was held on August 14, 1864, but its consecration took place on the Feast of the Assumption on August 15, 1864. It was on that day, in the presence of a jubilant crowd, that the statue of the Virgin, the one currently inside the chapel, was placed on the altar and blessed by Father Gabriel of Aiguebelle Abbey.
Inside the chapel, on the south side, is a small gilded wooden altar dating from the late 17th century. It is surmounted by the statue of the Virgin, which was placed there on August 15, 1864. Two wooden staircases, on either side of the altar, lead to the gallery, whose three tiers of seats are arranged in an amphitheater around the tower. The altar, steps, altarpiece, and tabernacle are listed as historical heritage by the Ministry of Culture, under the reference PM26000450.
Numerous paintings adorn the walls, most of them the work of the painter Léon Alègre, originally from Bagnols-sur-Cèze (Gard). These paintings were created between 1867 and 1869.
The paintings depict:
along the east and west staircases: the Flight into Egypt and the Adoration of the Magi;
on the faces of the vaulted arches: to the south, the Presentation of Mary in the Temple and Our Lady of Good Help; to the west: the Assumption and the Sorrowful Mother; to the north: the Holy Family and the Visitation; to the east: the Annunciation and the Marriage of the Virgin;
On the edges of the vaulted arches, four portraits appear: to the east: Saint Mark and Saint Matthew; to the west: Saint John and Saint Luke;
above the entrance door: between Saint Stephen and Saint Francis of Assisi, the Coronation of the Virgin.