Naval officers from the he LÉ William Butler Yeats, boarded the ship and detained it - approximately 110 nautical miles south of Mizen Head early this morning.
The French fishing boat is the sixth ship detained by the Irish Navy so far this year.
In June, a Spanish vessel was involved in an alleged incident in Irish waters close to Bantry Bay
Last year, there were 16 such detentions.
The Navy will escort the vessel to port, where An Garda Síochána will become involved.
