Located in the centre and almost at the heart of the Saint-Vincent hillside.

The construction of the sanctuary came from an idea around 1720 by the priest Pierre Bréan, who was vice parish priest in the village from 1705 to 1713 and greatly devoted to the Virgin Mary. In an agreement stipulated in 1725, the inhabitants of Grun and Valmignana committed to providing the land and the materials necessary, while Reverend Bréan committed to paying the works and furnishing the chapel. The temple was completed in 1727; participants at the inauguration festivities included the abbot Jean-Baptiste Perret, who in 1770 discovered the thermal water source.
The sanctuary quickly became a place of pilgrimage and votive offerings continued to increase, which were brought by followers who asked for gracious healing or conversion.

Extended in 1864, this small church has a nave, a choir, a sacristy and a small choir loft. There are plenty of votive offerings on the walls, beside the Carrying of the Cross; the brick altar, lying between four columns, once hosted a large painting of Mary, however it was stolen in 1992. Today, a shelf hosts a statue of the Virgin Mary in walnut which was a gift from a devotee.
Outside, a retracted area forms a porch. Worth noting, the fresco by Mus depicting the Virgin Mary welcoming pilgrims with open arms.

There were once numerous processions from the village of Saint-Vincent to Grun sanctuary; we particularly recall one at the end of May and the “rain” procession appealing for rain and for it to stop.