"As is the case in many other European countries, Belgium has implemented an identification system that relies on electronic identity cards in combination with a national register containing important identity data (name, address etc) for all Belgian residents. That register uses a national register number as a unique identifier, and this number is also stored on the national eID card.
In theory, since the card can be supported in private sector applications, it can be a useful tool for facilitating enrolment in electronic services. For instance, it would be easy to use the eID card as a customer loyalty card in retail stores. That would have the benefit of providing stores with reliable customer data. However, since the national register number is unique and never changes for any citizen, it would also allow stores to conduct potentially very invasive profiling by linking purchasing behaviour in various stores together. While other options would also be available to solve this problem, in Belgium the choice was made to simply prohibit private sector use of the national number without governmental authorisation.
This rule has been in place for a very long time now, but it was always difficult to enforce, since it required the government to actively pursue the matter. However, the GDPR has created a new avenue for enforcement: unlawful use of the identity card is obviously also unlawful processing of personal data, and therefore fineable by the data protection authority.
In a September 2019 ruling, the DPA issued a 10.000 EUR fine to a merchant that none the less used the eID card (and the register number) as a tool for generating its own customer cards. The fine was on the fact that the number was used contrary to the law, but also because the eID card was the only way in which customers could enroll. In the opinion of the DPA, no free and valid consent was therefore provided.
Thus, the GDPR can also play a critical role in facilitating enforcement of long existing laws."
Article provided by: Hans Graux, Belgium