At Saint-Eugène, in what seems like the middle of the night here. In fact, it's after 0200 (and after Matins; Lauds will happen after Mass).
The Salve puerule from Charpentier's 'Christmas Oratorio' (his Canticum in Nativitate Domini Nostri Iesu Christi H 414) is being sung at Communion, following the Et Incarnatus est from his Midnight Mass at Christmas during the Credo.
The Agnus Dei is from Charles Gounod's Messe en honneur de Sainte-Cécile; I recognised it but couldn't identify it, tsk. The day's page at Liturgia (the Schola's site) is here.