Manchester City's Aymeric Laporte raised money for French health workers fighting coronavirus by buying the 2012 Olympic outfit worn by late boxer Alexis Vastine at auction, before returning it to his family.
Vastine died aged 28 in a helicopter crash in 2015.
His father donated the outfit to a charity auction organised by French handball player Cyril Dumoulin.
“Thank you Aymeric. Your talent is great, your heart too,” said Dumoulin.
French media reports that Laporte's winning bid was 5,000 euros (£4,350).
Vastine, who won light welterweight bronze at the 2008 Beijing Games, moved up to welterweight at London 2012, where he was narrowly beaten via countback by Ukrainian Taras Shelestyuk in the quarter-finals.
He was one of 10 people to die when two helicopters collided seconds after taking off during the filming of a French reality TV show in Argentina in March 2015.
"When the facts speak more than words. Thank you Aymeric Laporte, who won this auction with the wish to leave this outfit to his father," Dumoulin wrote on Twitter.
Defender Laporte replied: “Thank you, especially for your actions against the virus and these auctions that help those who need it most. See you soon.”
Team-mate Raheem Sterling, Monaco striker Wissam Ben Yedder, cyclist Rudy Barbier and golfer Alexander Levy were among those to praise Laporte for his actions on social media.
Former Manchester United strikers Ruud van Nistelrooy and Louis Saha, and ex-Chelsea forward Didier Drogba are among those to donate memorabilia to the auction, which is raising funds for frontline workers in the battle against Covid-19.