The current parish church building dates back to the first half of the eighteenth century.
The church has a basilican plan with three naves covered by cross vaults and marked by six squared pillars with pilasters. The narrow choir is a straight apse. To the north, you can see the slope of the bell-tower foundation enclosed in the walls. The latter, which should date back to the XIV century, has an octagonal spire and a westerly facade with a tondo depicting a cross.
There is an interesting main altar, which dates back to the XVIII century, in black marble. Also worth noting, a canvas representing the martyr St. Sebastian, from the XVIII century, a single votive offering of a canvas, dated 1704, which takes its inspiration from the invasion of French troupes of Valle d’Aosta, an invasion that saved the village of Courmayeur.
The chapel to the left of the choir has an inscription that recalls Prince Umberto of Savoy and Princess Maria José’s honeymoon in Courmayeur in 1930.
Outside, in the square, the church presents a double flight of stairs with a pulpit. A hollow created using ice-axes hosts the statue of the priest, mountaineer and historian, Abbot Joseph-Marie Henry.