Are crypto exchanges legal in Germany?

Could you elaborate on the legality of cryptocurrency exchanges in Germany? I've been hearing conflicting opinions about whether they are officially sanctioned or not. As a country that prides itself on its robust financial regulations, it's crucial to understand the legal status of these platforms. Could you clarify if crypto exchanges operate within the legal framework in Germany, and if so, what are the key regulatory requirements they need to meet? Additionally, are there any specific licenses or certifications required for these exchanges to operate legally in the country?