If you do not comply with your obligation to register, you can expect severe fines. Depending on the case, these fines can reach up to EUR 100,000 or, in the case of intent, up to EUR 150,000. The same applies to the entry of incorrect data. In the event of data inconsistencies, you must also expect so-called inconsistency reports, to which you must respond within a short period of time, as there is also the threat of fines.
Please note that final decisions on fines are also published on the website of the Federal Office of Administration (so-called naming and shaming) and can thus have an impact on your reputation.