As a self-employed service provider, you can work across borders, without having to establish your business in Germany and to obtain any approvals and permits, but only notify your business.
Personal and business requirements
You are a national of a Member State of the European Union or your company's headquarters is in Iceland, Liechtenstein or Norway.
Self-employed in a "regulated profession"
If you want to work in a regulated profession, e.g. as a skilled craftsman, have acquired the necessary licences and qualifications in your home country and can prove this.
Regulated means that the requirement for your self-employment includes a special licence or qualification. You must prove that you have acquired the requisite qualification in your country of origin. For more information, click the navigation item Working with foreign professional qualification.
If you possess the required qualifications, you need not obtain an approval to pursue your profession, but notify the concerned authority of your intention to provide services, wherein the concerned authority would also be responsible for the accreditation of your professional qualifications. That would be, for example, the Chamber of Crafts and Trade for professions in skilled arts and trade, the Chamber of Architects for architects and the Chamber of Veterinarians for veterinarians. You may immediately start your operations following the notification. The notification shall be repeated every twelve months, in general, as long as you continue to intend to provide services. Significant changes to circumstances, which affect the conditions for the provision of services must be notified to the concerned authority also in writing with supporting documentation.
On the website of the European Commission you can check whether your work comes under regulated profession - available in three language: German, English and French.
If you want to offer a service in a non-regulated profession in Germany, you can perform these activities without prior notification to the concerned authority. For unregulated professions, the professional access or the profession is not linked to any specific public qualification requirement. That is, the profession can be exercised without governmental approval.
This is not true of services in areas, which are excluded from the European Services Directive, for example, healthcare, financial services, taxation, transport or gambling. Approvals and permits of the concerned authorities are required to be self-employed in these areas.
For more useful information on this subject in the European context, see Your Europe - Providing services abroad, Your Europe - Selling within the EU and Your Europe - Equal treatment.