Hi Mélanie,
this sounds like a complicated problem.
Using Autoindex, you could trigger a job when the "modification date" changes, however, that also includes changes to the index data of the document. To only act on changes of the document content itself, you would then need to start a workflow which uses the DocuWare REST API to check if the "ContentModified" Field of any of the sections of the corresponding document has changed.
Only then you can be sure that the document content has been modified.
Greetings from Germany,
Simon H. Hellmann
DocuWare System Consultant