Here is what happens (on an administrative level) before your defence:
Art. 11.4. To be defended, the thesis must first be submitted to the thesis
director, and, if applicable, the thesis co-director, and also to the members of
the jury for approval and to permit the drafting of the thesis report by the thesis
director. The thesis, the thesis report approved by all the jury members and that
concludes that the thesis can be defended, as well as the chosen jury, are
submitted for the approval of the director of the doctoral program concerned. The
printed version of the thesis must be accompanied by an electronic version.
5. At least fifteen business days before the scheduled date of the thesis defence,
the director of the doctoral program concerned must provide to the Dean's Office of
the doctoral student’s host Faculty, a copy of the thesis and the thesis report,
the jury’s composition and its approval.
For all this to take place, you should sign up with your program coordinator about 30
working days (6 weeks) before your planned date of defence, and your final thesis and all
paperwork should reach the Dean’s Office no later than 15 working days (3 weeks) before your
planned date of defence.
Bear in mind that the program coordinators and program (co-)directors may be away
(especially during holiday season), so if you are working to tight deadlines, ask them well
ahead of time whether they will be available on the date you need them.