The information at [1] (in French) clearly states that alternative methods remain available.
Here is the translation of an excerpt:
"Creating an Alicem account is not mandatory. Users remain free of using available alternatives:
- account creation on the specific service [Translator's note: this identification method is destined at the national SSO that is only one way of logging in the various public services]
- other electronic identification methods on FranceConnect [Translator's note: FranceConnect is the name of this SSO. This includes at least fiscal number + password and social security number + password and maybe other methods]
- traditional physical administrative procedures"
I am not necessarily a fan of this identification method and for myself I consider it less secure than a sufficiently strong, properly stored and regularly updates password. Still, the argument of locking the users or making the smartphone mandatory does not stand.
As for the collected biometric data, it is collected from the passport's chip, so technically the administration is already in possession of this data, there is nothing new here.
I see this as completely independent from facial recognition surveillance (hence mandatory), which in my opinion we must fight against.
[1] https://www.interieur.gouv.fr/Actualites/L-actu-du-Ministere...