There truly is no easy answer to this somewhat difficult question. In a German setting, etiquette depends on the environment and situation. If you want to play it safe, introduce yourself using your full name and wait for the response of your counterpart. If he or she only uses his or her first name, the stage is set for a more familiar setting. (Mind you, this is not a typical scenario in the English-speaking realm). Yet if he or she also responds with their full name, make sure to refer to your counterpart as “Mr.” or “Ms.”, respectively!
It is not uncommon to eventually transition into a more informal setting and switch from formal last names to a first-name basis. But who should initiate this transition? German etiquette tends to take a more conservative approach and suggests considering the age and job description of your counterpart. If he or she is older than you or has a higher job ranking, play it safe and don’t be the initiator!