Do you operate a business in Germany and generate more than EUR 24,500 in business income per year?
If so, you are required to file a trade tax return with your tax office. In this return, you declare the amount of your business income for the past calendar year (tax period). You must file a trade tax return for each tax period during which you operated your business (annually). You must submit the return electronically, for example via www.Elster.de. In doing so, you report additional additions or deductions based on your profit or loss (simplified: revenue minus expenses).
You must also specify the municipality in which you operate your business.

The tax office determines the trade tax assessment base and notifies you of it in a formal notice.
The tax office calculates the trade tax base by multiplying the business income by the tax rate of 3.5 percent. This base serves as the foundation for determining the amount of trade tax.

The tax office informs the municipality where you operate your business of the trade tax assessment base.

The municipality will send you a notice regarding the trade tax you are required to pay or that the municipality will refund to you.
The municipality calculates the trade tax by multiplying the tax base provided by the tax office by the municipality’s trade tax assessment rate. Each municipality sets its own assessment rate.

In its trade tax notice, the municipality also determines the advance trade tax payments you will be required to make in the future for the subsequent assessment period.

You must pay the amounts specified in the trade tax assessment notice and/or advance payment notices to the municipality by the due date indicated therein.