My conclusion :
The Tooltip macro package must be imported in the Admin wiki of a wiki farm.
Due to a bug, the tooltip macro is not rendered in wiki instances of the
farm because the resources of the macro (javascript, stylesheet) are
searched in the instance wiki (in place of the Admin wiki).
A workaround is to import the tooltip package in the instance wiki where you
want to use it.
Could someone confirm my thought ?
Best regards,
Maxime