
Changing jobs is restricted, especially early on -- you must notify the immigration authority in advance, and the minister can object within a set period.
Job changes on the Luxembourg Blue Card are not free. You must notify the immigration authority before changing employer, and the minister responsible for immigration has a window (around 30 days) in which to object to the proposed change.
Changing to a different sector requires authorisation, and moving into non-qualified employment means you fall outside the Blue Card and must apply under a standard worker category. Always clear an employer change with the authorities before starting, since an unauthorised switch breaches your residence conditions.
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