Over €425,000 in cash was seized by Revenue officers at Dublin Port during routine profiling yesterday.
The cash was found when a passenger was stopped and searched by officers, before leaving Dublin Port by ferry to France.
It is suspected that the cash is intended for use in criminal activity, Revenue says.
An investigation is under way and a man in his 40s is being questioned at Store Street garda station.
Today, the Dublin District Court granted Revenue officers a three-month cash detention order.
