The Sanctuary of Our Lady of the Trinity has a unique set of 70 stained glass windows: 14 large windows, 7 on each side of the nave, 14 bays illuminating the chapels and 42 stained glass windows in predella associated with the bays.

The artists Louis Barillet and Jacques le Chevallier put into use the technique of the Middle Ages. Glass roofs, bay windows, stained glass windows in predella constitute veritable mosaics of small juxtaposed glasses, tinted and fired in their mass. Hence the inimitable radiance of these vitrified wonders!