That would be us
To be fair: we do the opening verse, the hymn and all the antiphons in Latin; we do Ps. 109 in Latin but usually the second psalm in French on Gregorian tones, and we do the Magnificat (or Benedictus on Holy Saturday) in Latin.
The deacon does the readings, and intercessions, in French.
Four years ago, for the 100th anniversary celebration of our monastery, the monks went to the cathedral and sung solemn Monastic Vespers for the 2nd Sunday of Easter, all in Latin except reading and intercessions (which is the practice at the abbey). The cathedral was packed, so there is a “market” as it were. I was involved in that effort in a support role; the monks travelled by bus, but I took their vestments and a lectern in my car.