This means Chin, 60, need not face a trial scheduled in the Kuala Lumpur Sessions Court.
Her lawyer, Ambiga Sreenivasan, told reporters that the effect of the unanimous Court of Appeal ruling was that the charge had been struck out.
Earlier, the three-man bench led by Tengku Maimun Tuan Mat said any law, including court judgments, could not be applied retrospectively.
“The appeal is allowed,” she said.
Chin’s lead counsel, M Puravelan, had submitted that at the time his client was alleged to have committed the offence, a Court of Appeal bench had ruled Section 9 (5) of the Peaceful Assembly Act (PAA) as unconstitutional in the Nik Nazmi Nik Ahmad case in April 2014.
That provision in the law prescribed a fine of RM10,000 against organisers of any rally for failure to give a 10-day notice to police.
However, another Court of Appeal bench on Oct 1 last year, in the case of R Yuneswaran, had departed from the Nik Nazmi’s case, leading to the existence of two conflicting judgments.
Chin committed the alleged offence on Aug 29, 2015, just before Yuneswaran’s judgment.
Deputy Public Prosecutor Suhaimi Ibrahim said it was trite law that a later judicial pronouncement was binding.
“Since we have two conflicting decisions from a court, the latter ruling is the binding precedent.”
He said the High Court was correct to rely on Yuneswaran’s ruling.
Ambiga, who appeared with Puravelan, submitted that Chin could not be charged with an alleged offence that did not exist on Aug 29, following Nik Nazmi’s case.
“It will make a mockery of our justice system,” she said.
DPP Hamdan Hamzah, who appeared with Suhaimi, told the judges that court judgments were not law, as defined under the Federal Constitution.
On April 18 this year, the High Court in Kuala Lumpur had dismissed Chin’s application to strike out the charge.
Judicial Commissioner Mohd Shariff Abu Samah, relying on the Yuneswaran judgment, had said it was an offence to hold a rally without giving notice.
Chin, who is Bersih 2.0 chairman, was charged with failing to give notice to the Brickfields district police before organising the rally in front of the NU Sentral shopping complex, Jalan Tun Sambanthan, Brickfields, on Aug 29.