Short Answer
The financial authorities automatically place you into the highest single-tax bracket until you submit a formal request to change it.
Marrying your spouse will not automatically lower your monthly payroll deductions without an active bureaucratic intervention.
What Most Expats Don't Realize
You assumed the registration office notified the tax authorities of your marriage and waited for your net pay to increase. Instead, you remained locked in Tax Class 1 for eight months, watching over €400 of your hard-earned cash vanish into the state treasury every single payday. You faced a cumulative cash flow deficit of €3,200 before realizing you had to submit a separate application to fix the error.
What To Do
- Open the official "Elster" online tax portal and log in using your digital certificate.
- Download the paper application form "Antrag auf Steuerklassenwechsel bei Ehegatten" if you prefer physical submission.
- "Wir möchten unsere Steuerklasse auf die Kombination drei und fünf ändern." (We would like to change our tax class to the combination three and five.) — say this at the local tax office (Finanzamt) desk to adjust your monthly net income.
The Truth
The German tax office assumes you are single (Class 1) until you prove otherwise. They don't communicate with the registration office automatically regarding your tax class preferences.