I think I understand the question. I’m not sure if this is the right answer, but it returns the records you specified.

select *
from Document
where 
  Document.Doc_Num not in (select DocDOrigine from DocumentD) and
  Doc_Type = 'BLA' and
  Doc_Valide = 1;

Basically, the first WHERE clause is what you were missing. This is one of the easiest ways to write that, but it could easily have performance issues or need its own filtering to match better with the Document table.

Here’s another way it can be done, using an outer join instead of a sub-query:

select Document.* 
from Document
  left outer join DocumentD on
    Document.Doc_Num = DocumentD.DocDOrigine
where
  DocumentD.DocDOrigine is null and
  Document.Doc_Type = 'BLA' and
  Document.Doc_Valide = 1;

Edit:

I missed the DocDOrigine column from the example result set. I had to add some missing data from your question to the SQL fiddle to get it to return the expected result set. The SQL Fiddle link is:
https://sqlfiddle.com/sql-server/online-compiler?id=8af184de-67b4-49cf-a4fe-50148dc9b4eb

The queries to return that are:

select
  Document.Doc_Num,
  Document.Doc_Type,
  Document.Doc_Date,
  DocumentD.DocDOrigine,
  Document.Doc_Valide
from Document
  inner join DocumentD on
    Document.Doc_Num = DocumentD.Doc_Num
where 
  Document.Doc_Num not in (select DocDOrigine from DocumentD) and
  Doc_Type = 'BLA' amd
  Doc_Valide = 1;

And, the outer join variant:

select
  Document.Doc_Num,
  Document.Doc_Type,
  Document.Doc_Date,
  PrimDocument.DocDOrigine,
  Document.Doc_Valide
from Document
  left outer join DocumentD as OrigDocument on
    Document.Doc_Num = OrigDocument.DocDOrigine
  inner join DocumentD as PrimDocument on
    Document.Doc_Num = PrimDocument.Doc_Num
WHERE
  OrigDocument.DocDOrigine is null and
  Document.Doc_Type = 'BLA' and
  Document.Doc_Valide = 1;