The basilica describes itself as a sanctuary of Eucharistic adoration and divine mercy, and the Benedictine Sisters of the Sacred Heart of Montmartre lead its liturgy. Those who come for a night stay at the sanctuary's guesthouse and take turns before the Blessed Sacrament through the night, so that the prayer is never broken. It is not a parish, so weddings and infant baptisms are not celebrated there; the basilica notes that engaged and newly married couples often come for a night of adoration instead. Groups can plan a pilgrimage with the guesthouse team and should make contact well ahead.
Good to know before you go: book through the guesthouse page of the basilica's website, or reach the basilica at 35 rue du Chevalier-de-la-Barre, telephone +33 1 53 41 89 00. The guesthouse sets the evening arrival time, how the hours of the night are shared out, the sleeping arrangements and the contribution it asks, and it gives these when you reserve; ask too about a minimum age if you are bringing teenagers. During the day anyone may enter the basilica to pray without booking. Entry is free, silence is asked, and photography is not permitted in the nave.