Artists and creative professionals who are not citizens of the European Union (within the meaning of Article 20 TFEU) generally require a residence permit to enter and stay in Germany.
It is important to distinguish between a short stay and a longer stay, which is usually connected with moving to Germany. Nationals of some countries can enter Germany without a visa, while many require a visa (e.g. a so-called Schengen visa for a short stay); this applies to both short stays and longer stays. Here you can find information about different types of visas, application procedures and other aspects of visa application that you should consider.
The residence title also defines your access to the labor market. Basically, there is no access to the German labor market during a short stay, i.e. you are not allowed to pursue any gainful employment. However, the Employment Ordinance stipulates that many artistic activities (including paid ones) are not considered gainful employment and may therefore be carried out. For longer stays, access to the labor market is defined by the residence permit.
BMI information: Verpflichtungserklärung (declaration of commitment)