Administrators may only use powers for which they were granted (dét ournement depouvoir).
Furthermore, they may only make decisions on areas for which they are authorized or entitled according to e.g. the Government Accounts Law. Once they go ‘out of their limits’ their decisions are in fact not authentic. The administrator can even be held personally liable for it.
Why is the misuse of powers (of abuse) are not acceptable?
Abuse of powers (law) implies that the jurisdiction (the law) is used in a way that is not the intention. Certainly when applied by an administrator, this results in legal uncertainty. Each administrator is responsible for what is taking place on his policy area of responsibilities. However, once he moves on areas of responsibilities of his colleagues, without authorization, the chance for conflict of interest is high.