Advertising messages in the form of electronic emails are prohibited because they contravene the provisions of Directive 2002/58 and 2005/29 insofar as an automatic redirection of the user to said advertisement cannot be prevented and is carried out against his will - ECJ judgment case C-102/20 StWL (Städtische Werke Lauf ad Pegnitz GmbH).
The purpose of Directive 2002/58 is to protect users of a service against any form of unsolicited communication for the purposes of direct marketing.
This type of communication for the purposes of direct prospecting is authorized on the sole condition that the recipient has given his prior consent.