Short Answer Which rule applies to you depends on your permit type: EU Blue Card holders only notify the authorities of a job change during the first twelve months — and after that, nothing at all — while ordinary work permits under §18a/18b can stay physically tied to one employer on the green supplementary sheet (Zusatzblatt) until you have it amended. Confusing the two regimes is how people lose signing bonuses. What Most Expats Don't Realize You held a general work permit, assumed the employer restriction dissolved automatically on your one-year work anniversary like your Blue Card colleagues claimed, and signed an offer with a competing firm. When you tried to onboard, the compliance team found your Zusatzblatt still legally bound to your old company, forcing you to delay your start date and miss out on a signing bonus. You suffered an immediate loss of €3,000 because you read the rules for a permit you did not hold. What To Do * Open your passport case and read the exact binding text on your green supplementary sheet — if a company name appears there, that restriction is live regardless of how long you have worked. * For a Blue Card, no appointment is needed: notify during the first twelve months, do nothing afterwards. For a §18a/18b permit, book a residence permit amendment before resigning. * "Ich beantrage die Änderung der Nebenbestimmungen meines Aufenthaltstitels für meinen neuen Arbeitgeber." (I apply for the amendment of the conditions of my residence permit for my new employer.) — use this at the immigration office if your supplementary sheet names your current company.