To back up Today_Only and Medea, the last time I was at the dentist the DH - who has been working here many years - mentioned that whatever authority checks these things has now asked her to submit proof of German competency (B1 or B2, can't remember which). This had to do with credentials, not permits, if I understood correctly. Apparently this is a new requirement.
The DH is non-EU, don't know if that plays a part, or not.
(Sorry for the vagueness, but I have trouble concentrating on small talk when sharp implements are in use.

)
Anyway, hopefully one of the EF members working in the field will chime in soon with more concrete information.