In a position paper, the BvD explains why the activity of the appointed data protection officer (DPO) does not constitute a violation of the Legal Services Act (RDG). In a well-reasoned decision of 12/03/2021, the North Rhine-Westphalia Lawyers’ Court (Anwaltsgerichtshof NRW) also confirmed the BvD’s legal opinion that the activities of the DPO within the scope of Art. 39 DPA do not conflict with the RDG.
The reasoning in keywords: Art. 39 GDPR explicitly includes legal advice on data protection. Accordingly, this is permissible under Section 3 RDG due to authorization in another law. Even if this were not so, this would constitute a permissible secondary activity within the meaning of Section 5 RDG.
Here you can read the complete BvD position paper (German language).