Karlsruhe police spokesman Ralf Minet said the boys were caught up in "a delirium of hormones" and received less than $400 for the jewelry from a gold dealer, The Local.de reported Tuesday.
Minet said the pair used their ill-gotten gains to fund a trip to a local brothel.
"One could still see a delighted smile on the faces of the thieves during their interrogation," Minet said.
"But the little rascals' smiles, who are not unknown to the police by the way, disappeared soon enough, especially because they will have to pay for the reversal of the transaction out of their pocket money," he said.
The boys were both arrested on theft charges.