Detector dogs Harvey and Marley were both used in the operation
Revenue officers in Cork have seized cash, unstamped cigarettes and a car.
The discoveries were made when they conducted a number of searches under warrant at premises on the north side of the city.
In an intelligence-led operation officers seized €15,015, suspected to be the proceeds of or intended for use in criminal activity.
This was seized in accordance with proceeds of crime legislation.
A 2011 Skoda Octavia car and 8,200 unstamped cigarettes were also seized.
Revenue say the cigarettes represent an estimated loss of to the exchequer of €3,900.
Detector dogs Harvey and Marley were both deployed in the operation, during which the cash and cigarettes were found concealed in furniture and elsewhere at a number of the premises.
Revenue officers questioned an Irish man aged in his 60s, a Moroccan man in his 30s and a Ukrainian woman in her 50s.
Files are being prepared with a view to prosecution.