The captains of two Irish fishing boats have been questioned by the authorities in France on suspicion of fishing illegally.
It is understood the vessels were escorted into the port of Brest yesterday after they were allegedly seen in a zone where Ireland does not have fishing rights under EU law.
The captains face fines of €25,000 each if they are found to have been fishing illegally.
A spokesman for the Department of the Marine confirmed that the Department was aware of the matter, but said it was not an unusual occurrence.
"We also detain foreign vessels for fishing illegally from time to time. It can be for a number of things, including for fishing the wrong species. The countries of the European Union have an agreement on these issues."
The department said it was not aware of the names of the vessels concerned.