Unlike other core state institutions, such as the German Parliament, the Federal Council, or the Federal Government, the rules of procedure of the Federal Constitutional Court are not anchored in the Constitution. This legal loophole is closed pursuant to § 1.3 of the Federal Constitutional Court Act (BVerfGG), according to which the Federal Constitutional Court (FCC) gives itself rules of procedure, which are adopted by the plenum.
The Rules of Procedure are divided into two parts. Part A regulates provisions on the Organisation and Administration of the FCC (§1 – §19 GOBVerfG), whereas Part B, which is again subdivided into ten titles, entails regulations on supplementary procedural provisions (§§20-73 GOBVerfG). The Rules of Procedure govern inter alia details on the drawing of lots (§ 38 GOBVerfG), on the recording of the oral proceedings (§ 24.3 to 7 GOBVerfG), on the casting of a special vote and the notification of the voting ratio (§ 55 GOBVerfG) and on the chairmanship and representation of the so-called delay chamber.
The rules of procedure are adopted by the plenum, the assembly of the constitutional judges of both Senates. Pursuant to §2.4 GOBVerfG, the plenum constitutes a quorum if at least two-thirds of its members - eleven judges - are present. It decides by a majority of the participating judges (corresponding application of § 15.4 sentences 2 BVerfGG). The Rules of Procedure are then published in the Federal Law Gazette (§72 GOBVerfG).
The Rules of Procedure rank below those of a simple federal law. They are merely an internal law and, therefore, not suitable to establish legal effects vis-à-vis third parties. They may only regulate the internal procedural rank, but they are specifically not a suitable place to close actual or alleged loopholes in the BVerfGG. The Rules of Procedure solely create a self-binding effect for the FCC.
Translations into English and French, as well as the German original, can be found on the Website of the FCC:
https://www.bundesverfassungsgericht.de/EN/Verfahren/Rechtsquellen/rechtsquellen_node.html