Sorry about the general lack of accents in the text. It should read: Célébrons sans cesse de Dieu le bontés.
There are versions at two pitches - one starting and octave above middle C, and one on middle C, to accommodate higher and lower voices. The version as a round plays once through "in unison" (only one part) then three times three with all four voices. The voice that starts is emphasised throughout.
Copied from some sheet music given to me by Kazimira:
- Célébrons sans cesse (pdf)