Not all self-employed persons are obliged to join a social insurance fund.
This is because the obligation to affiliate is linked to the obligation to be insured. Therefore those who are not included in the scope of the social status are not obliged to affiliate.

Among others, this applies to:

• journalists, press correspondents and persons who enjoy copyrights, provided that they already fall under another, at least equivalent social status
  
  
• persons who are de facto self-employed but who according to social security regulations are given an employee status
  For example: if you are an employee and in addition you perform similar activities for your employer under an independent contractor agreement, you are considered to be tied to an employment contract for all your activities.