This is an interesting little piece by Dupre from his 24 Inventions. The score calls for Voix Celestes on the manuals and an 8' flute for the pedals. The Klais organ has a Vox Coelestis on the Positive, but it doesn't go all the way to bottom C, it starts an octave up. This is no problem for this score. The Gedactbass provides the flute sound for the pedals.
I particularly like the natural crescendo and decrescendo that is written into the music starting at about 1:30
seconds. The last few bars call for a bit of double pedaling - nothing too strenuous; it could easily be played with the left hand on manuals if required.