The story, first published by investigative outlet OKO.press, said Braun was among the recipients of the Emil Czeczko Peace and Human Rights Award.
The prize is given by a Belarusian foundation known for its close ties to the Minsk government and for supporting Kremlin narratives.
Speaking at the Warsaw Citadel during a ceremony for Polish soldiers ahead of Poland's Independence Day, Kosiniak-Kamysz said he was deeply troubled by the reports.
"I am very concerned that one of Poland’s MEPs, Mr. Grzegorz Braun, has been honoured by the Belarusian regime. It’s a very dangerous situation," he said.
He noted that Emil Czeczko, the foundation’s namesake, was a Polish soldier who defected to Belarus in 2021 and later appeared in Belarusian propaganda broadcasts criticising Poland’s handling of the border crisis.
"Czeczko was a deserter who betrayed Poland," Kosiniak-Kamysz added.
"I hope this award will be firmly rejected, because accepting it would go against basic principles of patriotism."
The minister also said accepting the award could be seen as supporting attacks on Polish soldiers and border guards protecting the country's eastern border.
Braun, a far-right politician from the Confederation of the Polish Crown party, has not yet commented on the award.
The European Parliament lifted Braun’s immunity in May 2025 over a case linked to his interruption of a Hanukkah event in the Polish parliament two years earlier.
According to OKO.press, the foundation typically recognises figures supportive of Moscow and Minsk.
Czeczko was found hanged in his Minsk apartment in 2022, according to Belarusian authorities.
Before defecting, he had received a suspended prison sentence in Poland for domestic violence against his mother.
(ał)
Source: PAP, IAR, OKO.press