Well instead I will make it short and only come to the conclusion:
thanks for the informations I went have a look in the log.
the URL sent to Google API in v3 does not include any email or user information.
It looks like this
https:/ /www. googleapis.com/calendar/v3/users/me/calendarList?key=AIzaSyBhdYdkq-wy-bYoWWYJeKrEc9t6GAZF_wQ&pp=0
The user parameter sent is only : "users/me
Which leads, as I guess, to either:
* the Google board to select accounts identified on this computer
* The looged account if so (what happens to me eve when i'm not logged any more)
So I guess there IS a trouble where it could be possible to send the email parameter in the URL since it's not right now.