Good morning, everyone,

I am new to the forum. It is nice to e-meet you.

For some time now I have been tremendously curious to find what version (mode/tone/whatever) of the Miserere Mei and De Profundis psalms are being sung during the procession of the clergy at Monseigneur Marcel Lefebvre's funeral mass as can be heard in the beginning of the recording below.

At first it sounded a little bit like the "De Profundis parisien" as recorded by the choir of Notre Dame de Paris under Pierre Cochereau, but then not so much as the chant in the Requiem mass of the esteemed Monseigneur has a much more gregorian sound to it (and, of course, they don't just sing the De Profundis but the Miserere Mei as well).

Would you be able to help me? Thank you very much in advance.

https://www.youtube.com/watch?v=lHf156nvCr0