On June 30, 2009 German Federal Constitutional Court passed its judgment on constitutionality of ratification of the Lisbon Treaty. The key part of the decision is the following:
4. a) The Act Extending and Strengthening the Rights of the Bundestag and the Bundesrat in European Union Matters (Bundestag document 16/8489) infringes Article 38.1 in conjunction with Article 23.1 of the Basic Law insofar as rights of participation of the German Bundestag and the Bundesrat have not been elaborated to the extent required taking into account the provisos that are specified under C. II. 3.
b) Before the entry into force of the constitutionally required legal elaboration of the rights of participation, the Federal Republic of Germanyʼs instrument of ratification of the Treaty of Lisbon amending the Treaty on European Union and the Treaty establishing the European Community, signed at Lisbon, 13 December 2007 (Federal Law Gazette 2008 II page 1039) may not be deposited.
In brief, the Lisbon Treaty is not infringing the German Basic Law, however, the legislature did not comply with constitutional requirements when implementing constitutional guarantees of participation at European level. Accordingly, national legislation has to be changed, before ratification process can be completed.