The substantive criminal law is the principle “no punishment without law” (nulla poena sine lege shaped), and he enjoys constitutional status (see Article 103, paragraph 2 of the Basic Law). This principle includes the following individual bids, two of which the legislator and two directed to the right users:

• Definitely bid – nulla poena sine lege certa: The text of the law must be determined accurately. The legislature is not prevented from also use terms that require a score of Legislative user (ex: “high damage” and “reprehensible”) if the facts are no different tangible and the conceptual content of the respective terms with generally accepted methods of interpretation can be determined.
• Retroactivity – nulla poena sine lege praevia: Had the time of the crime criminality requirement, as the law valid. Retroactive criminal liability is not possible. According to prevailing opinion, the related conditions but not on the prosecution, but only to the substantive criminal law. This allowed the statute of limitations for murder in the Federal Republic of Germany are repeatedly extended up to the present system (no statute of limitations). An exception to this is – for the exclusive benefit of the perpetrator – the principle of so-called lex mitior, which is a revision of the law, the new version, unless it is milder.

In exercise of the activities listed above are available for the purposes of providing services:

• Attention to requirements of the following institutions: Ministry of Finance and Public Credit, Ministry of Trade and Industry, the Mexican Social Security Institute, National Fund for Workers’ Housing
• Monitoring and care of audits by the following agencies: Ministry of Finance and Public Credit and the Mexican Social Security Institute
• Recourse such as: Revocation against decisions of the Ministry of Finance and Public Credit,  Dissatisfaction with the Mexican Social Security Institute, Dissatisfaction with the Institute of the National Housing Fund for Workers
• Introduction of the trials of: Annulment before the Federal Tax Court and Fiscal