Castro has reportedly attracted interest from the club side of Bafana Bafana midfielder Bongani Zungu, according to French sports newspaper L'Equipe.
Sundowns last month announced the sale of the Colombian striker to Kaizer Chiefs on December 16, three days before he was unveiled at Naturena.
According to the report released in the daily paper on New Year's Day, Amiens are set to sign Castro from The Brazilians.
However, asked by KickOff.com whether the club had any knowledge of interest in Castro's services from France, Sundowns spokesperson Thulani Thuswa responded: "I don't know, no.
"He's no longer our player, he's already signed to Chiefs. It's up to them if they want to send him [to France]," he further commented.
Chiefs spokesperson Vina Maphosa is currently out of the country and stressed that the club's official re-opening for 2018 is only on Wednesday, January 3.