The Karlsruhe Court's ruling will have a direct impact on the reform of the EFSF agreed at a special eurozone summit on 21 July.
Experts expect the Court to approve the government's participation in the Greek and Irish bailouts, but will establish additional requirements regarding involving the parliament in similar decisions in the future.
A group of Eurosceptics around conservative MP Peter Gauweiler (CSU) filed a constitutional complaint with regard to the country's participation in the multi-billion-euro bailouts in May 2010. The oral hearing took place in July 2011.
MP Michael Stübgen, European affairs spokesman for the CDU/CSU group, told EurActiv Germany in an interview that "as regards to the Court's ruling on 7 September parliament's control over EFSF instruments has to be strengthened".
The parties in Germany's coalition – the conservative CDU/CSU and the liberal FDP – agreed last week on a multi-level approach to involve the German Bundestag in future EFSF decisions. The main idea is that the government needs parliament's approval before it can agree in Brussels on new EFSF rescue packages, but will have an extended margin to decide on technical implementation of EFSF decisions.
The coalition has announced its intention to bring opposition parties the SPD (Social Democrats) and the Greens on board, but will negotiate the final agreement on parliament's participation rights only after the court's ruling.
MP Michael Roth, spokesperson for European affairs at the opposition SPD, told EurActiv Germany in an interview that he expects a "parliament and Europe-friendly decision".
The German Bundestag is expected to decide on 29 September on the extended EFSF. The Bundesrat, Germany's second chamber of the federal states (Bundesländer), is expected to decide in an extraordinary session that day or the next.
In the meantime, economics professor Wilhelm Noelling, one of the plaintiffs to Germany's Constitutional Court, said the euro could only be "made functional by limiting it to a maximum of seven strong countries".
"The other countries should recognise the beauty and efficiency of individual made-to-measure solutions and/or alliances and reclaim them for themselves," he said, quoted by Reuters.