A Hong Kong man was sentenced to three months in jail on Wednesday for wearing a T-shirt with "seditious" slogans from the huge and at times violent democracy protests in 2019.
Chu Kai-pong, 26, was arrested and charged in November before boarding a flight to Taiwan at Hong Kong's International Airport and has since been remanded.
The court was told Wednesday that the airport's security guards had spotted Chu wearing a T-shirt with the words "Free Hong Kong" in English and "Liberate Hong Kong, revolution of our times" in Chinese, and reported him to the police.
The latter phrase was found to be "able to incite secession" in the first trial under a sweeping national security law Beijing imposed on the financial hub in 2020.
In that earlier trial, a motorcyclist carrying a flag bearing those words was sentenced to nine years in jail.
Judge Victor So, one of the justices handpicked by the government to try national security cases, said Wednesday that Chu had "knowingly broken the law" despite previous court verdicts over the slogans.
Chu had pleaded guilty to one count of "doing acts with seditious intent" and one count of "possession of seditious publications" earlier this month.
He had also been in possession of another T-shirt with the English slogan "Hong Kong Independence", according to the court, while his luggage contained another T-shirt and three black flags -- a colour donned by 2019 protesters.
Chu's lawyer had argued that freedom of thought was not restricted by law and the seditious intention found in the words might not be the defendant's intent.
The prosecution said that by displaying the slogan in public, Chu could incite others to try to separate Hong Kong from China.
Since the national security law was enacted, the pre-existing charge of sedition -- a once little-used legal hangover from British colonial rule -- was dusted off and used to clamp down on anti-government speeches and acts.