The English translation (via Google) of the linked article states:
The Second Senate of the Federal Constitutional Court (BVerfG) has
upheld the constitutional complaint of a man who, after being legally
acquitted in a murder trial, was tried again years later for the same
charge (judgment of October 31, 2023, case number 2 BvR 900/22).
In 1983, Ismet H., now over 60 years old, was legally acquitted of the
charge of raping and killing 17-year-old Frederike von Möhlmann.
However, the proceedings against the man were reopened in 2021 due to
new evidence - on the basis of a regulation that had recently been
introduced into the Code of Criminal Procedure (StPO) by the then
GroKo government. Ismet H. attacked exactly this § 362 No. 5 StPO with
a constitutional complaint. The BVerfG agreed with him on Tuesday.
BVerfG: “Article 103, paragraph 3 of the Basic Law is a matter of
balance and must not be relativized”
The Karlsruhe judges declared Section 362 No. 5 StPO to be void. The
provision is incompatible with the prohibition of multiple
prosecutions in Article 103 Paragraph 3 of the Basic Law (GG) and the
prohibition of retroactivity (Article 103 Paragraph 3 in conjunction
with Article 20 Paragraph 3 of the Basic Law). "Art. 103 Para. 3 GG
grants the principle of legal certainty absolute priority over the
principle of material justice," said the court. This priority decision
is also absolute and is not open to relativizing the ban by weighing
it against other legal interests of constitutional importance. When
viewed systematically, Article 103 Paragraph 3 of the Basic Law
appears to be “balanced,” according to the court.
The legal certainty created by a legally binding judgment also extends
to the fact that it is not called into question by the emergence of
new facts or evidence. The individual should be able to trust that
after a verdict they cannot be prosecuted again for the facts in
question. If the legislature had the right to strike a different
balance between legal certainty and the state's right to punish,
Article 103 Paragraph 3 of the Basic Law itself could not justify the
defendant's trust in the validity of the criminal judgment issued in
his case and thus legal certainty for the individual," said the court
In the opinion of the BVerfG, the application of Section 362 No. 5
StPO to proceedings that had already been concluded by a final
acquittal before the provision came into force also violates the
prohibition of retroactivity (Art. 103 Para. 3 in conjunction with
Art. 20 Para. 3 GG) . There is a “real” retroactive effect, which is
not admissible in exceptional cases. “Those who have been acquitted
can trust that the legal force of the acquittal can only be broken
based on the previous legal situation,” said the court. The principle
“ne bis in idem” (not twice in the same matter) recognizes the need to
protect trust in an acquittal criminal verdict. Art. 103 Para. 3 GG
gives this protection of trust constitutional status.
Before the law struck down in this case was passed, German criminal law created a statutory right for criminal defendants who were acquitted to not be retried for the same offense.
The German Constitutional Court held as a matter of German Constitutional law by combining Art. 103(3) and Article 20(3) of the German Basic Law (basically, Germany's Constitution), that the comfort provided by this statutory right to pre-2021 criminal defendants who were acquitted could not be changed by a post-2021 law. It isn't clear to me if this German Constitutional Court case has prospective application to acquittals taking place after 2021.
Article 20(3) states (in a human made translation from the German Basic Law link): "(3) The legislature shall be bound by the constitutional order, the executive and the judiciary by law and justice."
Article 20(3) had previously been held to prohibit retroactive legislation. In this case, a law/regulation enacted in 2021 reopened an acquittal verdict that had previously been final and not subject to being reopened.
It isn't clear to me, given the logic of the ruling, that this ruling necessarily rules out the possibility of a trial following an acquittal based upon new evidence for convictions entered after the new law was adopted in 2021 - a fact pattern that was not before the court. It certainly does say, however, that if you have a final acquittal not subject to any further judicial review entered prior to the new 2021 law, the government can't take away the certainty that you would not face a new trial based upon this new law retroactively.
This ruling seems similar in structure to U.S. court rulings (in some U.S. jurisdictions, but not others) holding that once claim that could be asserted in a civil lawsuit is barred by the statute of limitations, it may not be revived with legislation passed after the statute of limitations has run.
It is possible that this ruling is stronger than I have supposed and also includes as a hybrid of Article 103(3) and 20(3), a true double jeopardy protection arising from the German Basic Law. But, without access to more in depth text from the ruling and analysis from lawyers familiar with German criminal law and procedure, it is hard to tell. To a common law mind, a holding like that would be dicta and not a binding precedent, but German law treats case law differently than common law systems do, so the challenge to the holding as applied to post-2021 cases as dicta would probably not be appropriate in German law.
It could simply be that the prior statutory prohibition on double jeopardy in German criminal cases prevented the issue from facing German Constitutional Court review since the prior law didn't violate the German Basic Law prior to 2021.