7.2 - calendar not localized?

I have an instantiation form that use 2 calendar widgets but they appear to be only english localized

I am using the 7.2 community edition and testing using the studio.

Using the ACME Organization:
Connected user: walter bates
Preferences / language : french

The portal is localized in french (Bienvenue, Paramètres...) but not the date picker.

Is it a bug or dit I miss something?