IDW Accounting Principles (IDW AcP)

IDW Accounting Principles are issued by the Auditing and Accounting Board (the IDW’s main technical committee) or by another technical committee, as appropriate and set forth the views of the [German auditing] profession on specific accounting matters. A German public auditor should carefully examine whether the IDW Accounting Principles are relevant to any given individual audit engagement.
Deviations from IDW Accounting Principles are to be appropriately disclosed in writing (e.g., in the long-form audit report) with detailed justification.
If a German public auditor does not observe IDW Accounting Principles without good reason, this departure from the views of the profession could count against him or her in respect of claims to damages, proceedings brought before the professional supervisory body or criminal proceedings.