The Tynecastle side are desperately on the hunt for new recruits as they come out of the winter break in bottom spot in the Premiership.
They've targeted exciting 19-year-old prospect Herrmann, who plays for Wolfsburg II in the fourth tier of German football and are keen to bring him to the capital.
However, Wolfsburg sports director Pablo Thiam has made it clear they have no intention of selling Herrmann this transfer window because the club are in the midst of an injury crisis.
He said: "I can confirm there was an enquiry from Hearts to sign Charles.
"But we will not be selling any players during this transfer window and the player has been told this and made aware of the reasons.
"We currently only have three fit strikers in the squad and we cannot afford to lose any.
"Charles is also a little behind in his own fitness. There were reasons for this and he knows this.
"But let's not forget he was only playing with the Under 19s last season and he is someone we think will have a big future here."