Hi, I would like to display invitation in calendar but never send any confirmation (even when importing, moving or removing events). Is this possiible ?

Hi Patrice,
unfortunately this cannot be set through eM Client, as this depends on your calendar and server settings.
A possible workaround would have to be to not send your messages immediately (Tools > Settings > Mail > Send > uncheck the option to Send messages immediately) and then delete the triggered invitations from Outbox.