In some countries, national civil service employment has nationality restrictions. For example:
- In Germany, the civil servant must be German or be an EU national (source). However, someone told me that in the recent past, only German nationals could be civil servants.
- In the United Kingdom (pre-Brexit), civil servants must have the nationality of the UK, Ireland, Switzerland, Turkey, a Commonwealth State, or a EEA state (source).
- In Belgium, the national civil service is open to Belgians, EEA nationals, or Swiss nationals (source).
Is there a general EU rule that implicitly or explicitly means that any EU national is eligible to work for (most) jobs in the national civil service of other EU countries? This article which states that EU national civil servants will not lose their right to work as UK civil servants post-Brexit appears to imply that this right is currently derived from their EU nationality, but does not expilictly say so.
I'm aware that some particular roles, such as spy or soldier or President, may have specific nationality requirements, but in this question I'm interested in the general case.