Using Schwa in French

The schwa symbol [ə] is present in the French language and IPA as well as in many others.
As a diction teacher, what I notice when we use it in French singing, is that we equate it to schwa in languages such as English, where it often implies an unaccented syllable. I find that it disrupts the general resonance of the phrase and somehow has the voice "drop". Let me explain.

In French, we speak of inflections. For example, while the inflection in the word "Ensemble" [ãsãblə] goes to [sã], I prefer to write and pronounce the final syllable as [blœ]. This applies particularly well to singing because it keeps the singer's resonance and instrument engaged: when we sing [œ], our lips are in the [ɔ] position and our tongue in the [ɛ]. It all comes down to nagging about never letting the voice drop and staying engaged, which is very representative of proper French. To achieve this, using [œ] is way more efficient than using [ə] in my opinion. While one can still IPA a text using the [ə], I encourage you to switch over to [œ], to train the brain to equate the way they sound. You can still remain aware of which syllables require [ə] and which require [œ], but pronounce them [œ] consistently.

Whether you like to write such syllables with [ə] or [œ], most of the time composers set that syllable on an actual pitch and/or note value. Thinking of the final sound as [œ] then helps us carry over the engagement of the voice all the way to the end of the phrase.