Bonsoir Jerome,
Thanks for your complete feedback.
So just change the match. You can not use "permissive" match here on your select field in your search type, because all the values are the common term "Choix". If you use "permissive" match SEBLOD is searching "Choix" or "1" (2 or 3), so all "Choix" is always tru, all results are return.
Try "Exact" here. Which in 99% always the case for a select field.
To avoid any issue I advise you to use in all "select" fields such as simple dropdown, checkboxes the syntax text=value.
Replace your first dropdown field value by "Choix 1=choix1" (or Choix1=1). In this case you use "Any World Exact" match too because your value is a unique world (no space).
Regards.