Constitutional review in Germany

The constitution (Grundgesetz) of the Federal Republic of Germany establishes a separate Federal Constitutional Court of Germany (Bundesverfassungsgericht) that is empowered with reviewing acts of the legislature (so mainly from the Federal Republic Congress - the Bundestag) for their constitutionality.
Most states (Bundesländer) also have separate courts for the according purpose. These are separate Supreme Courts that do not deal with appellate cases in civil and criminal law - but rather, just in constitutional cases.
The Federal Constitutional Court of Germany can also review and reject constitutional amendments on the grounds that they are contradictory to the rest of the Federal Republic Constitution ("Verfassungswidriges Verfassungsrecht"), unlike, for instance, the Supreme Court of the United States and the Supreme Court of Canada.