The president's signature was the final step in Germany's ratification of the Lisbon Treaty, after the reforms received wide approval in the parliament's lower and upper chambers - the Bundestag and Bundesrat respectively - earlier this month.
The domestic reforms are designed to increase German politicians' involvement in European lawmaking after high-profile petitions to the country's constitutional court on the treaty's compatibility with German law had stalled the process (EurActiv 12/02/09).
The constitutional court said claims made by Dieter Spethmann, a former chairman of large German steelmaker Thyssen, were illegitimate.
Spethmann had deemed the reforms "careless and superficial" and demanded a provision be added rendering the treaty valid only under a ruling issued by the same federal court in Karlsruhe in June.
Under the new laws, Germany's federal government is now expected to inform MPs about all EU matters "comprehensively, as early as possible, continuously and in writing".
A new veto right can be employed by the country's national parliament in areas where the EU's decision-making touches German spheres of interest.
Apart from Germany, approval from the Czech Republic, Ireland and Poland is still outstanding. Czech President Václav Klaus and Polish President Lech Kaczynski have yet to sign the treaty, despite its approval in their parliaments.
Indeed, Czech approval is now looking more uncertain, after British opposition leader David Cameron wrote to Klaus asking him to hold off ratification (EurActiv 24/09/09).
According to a report on the Daily Mail website, Cameron reassured Klaus that if the president were to hold up the treaty, he would stage a referendum in Britain if he wins power in elections due by next May (EurActiv 24/09/09).
Ireland will vote on the treaty in a referendum on 2 October, after it was rejected by voters there last year.
