Key legal question
Whether the dispute over Berufsbildungsfonds contributions is public-law or private-law in nature and which federal appeal route applies.
Extracted holding
The claim is public-law in nature; the proper remedy is the public-law appeal, and the subsidiary constitutional complaint is inadmissible.
Extracted reasoning
BBG is public law, Art. 60 BBG is hoheitlich, and the contribution duty stems from a federally authorized general binding declaration, not from association or contract law.