Customs officials on Friday found $1.3 million in luggage at Dusseldorf Airport.
Police said that they have started investigating whether the money is connected with drug trade, since most of the money was in small notes.
The notes were found in the luggage of two travellers who were flying to Turkey.
The men, who both live in western Germany, have been released after questioning.
The men, aged 38 and 50, are accused of transporting more than 10,000 euros into a non-European Union country.
The police said: “Sums of money over 10,000 euros that are transported outside the EU must be declared.
“Failing to register the transport of more than 10,000 euros can be penalised with a fine of up to one million euros.
“Authorities have confiscated the money.”