Banknotes with a value of at least 50,000 euros fluttered out of a skyscraper in Mainz.
As the police announced on Tuesday, several residents of the high-rise complex reported the "extraordinary storm" on Monday afternoon.
Residents have already collected a five-digit amount and handed it over to the police.
A spokeswoman stressed that pocketing the banknotes is not allowed.
It is a case of embezzlement, which could lead to a fine or even imprisonment.
The owner of the large sum of money is still unknown.
So far, no one has reported, said the spokeswoman.
If the owner does not report by Tuesday, the money will be handed over to the lost and found office of the city of Mainz.
The rightful owner can collect the money upon presentation of appropriate proof.
According to the police, it was unclear from which building the rain of money came and why the banknotes had flown out of the house.
"The suspicions range from money sewn into a pillow that accidentally fell out when knocked out, to money derived from a crime," it said.
Südwestrundfunk had previously reported.Keywords: