German authorities are investigating documents found in the car of former Miami Vice star Don Johnson that detail transactions worth $8bn (£5bn).
Don Johnson starred as a vice officer in 1980s hit Miami Vice
But a customs spokesman said there was "no indication" of illegal activity and that it was not a criminal investigation.
The actor's car was stopped for a routine check on the Swiss-German border as he entered Germany in November.
The documents were photocopied but not seized and he was allowed to continue his journey without formal questioning.
"There is currently no indication of illegal
transactions," customs spokesman Wolfgang Schmitz said.
"There is no criminal investigation and prosecutors are not involved."
Mr Schmitz declined to give details of the documents, which are still being evaluated.
Banks have had to be contacted, meaning the process can take some time.
The amounts involved also led German customs to alert United States authorities, Mr Schmitz said.
Such checks are regularly carried out on the border because Switzerland is not a member of the European Union and has strict bank secrecy laws.
Johnson, 53, found fame in police series Miami Vice in the 1980s, and went on to play police inspector Nash Bridges in another TV show.
He has also appeared in movies including 1996 hit Tin Cup, with Kevin Costner.