Version: O365 E3 - French version
When closing an event after consulting it in the calendar, we get this window:
The first button is good because it allows to Save changes. The second one is misleading because "Annuler" is the same as the third one used to Cancel. It should be labeled "Ignorer", to be consistent with terminology used in the question at the top asking if we want to save or ignore changes, and allow users to choose the good one the first time.