Federal police said they ordered part of the airport's Terminal 2 closed to look for the man following the incident at 3.30 p.m. (1430GMT, 9:30 a.m. EST).
An airport security instrument alerted officials to possible explosives as the man's laptop was being checked, police said. He then hastily left the scene as officials continued to check the computer.
It wasn't immediately clear whether there were actually any explosives or whether it was a false alarm, federal police spokesman Berti Habelt told n-tv television.
Airport spokesman Florian Engert said a dozen aircraft were unable to depart.
