The INLA admitted responsibility for his death in 1995
Human remains recently recovered in a French forest near Rouen are those of one of the 'Disappeared' Seamus Ruddy.
The remains were discovered by the Independent Commission for the Location of Victims' Remains (ICLVR).
Mr Ruddy was a 33-year-old English teacher from Newry who lived in Paris when he disappeared in May 1985.
The INLA admitted responsibility for his death in December 1995.
In February 1999, information emerged suggesting that his body was buried at a location near Rouen - but previous searches there by the ICLVR had not recovered his remains.
Tánaiste and Justice Minister Frances Fitzgerald said: "Our thoughts today are with Seamus Ruddy's family.
"While I know that this news will be bring mixed emotions for them, I hope the confirmation of the discovery of his remains will provide some comfort to his family after such a long period of suffering for them.
"I want to thank the Commission for the Location of Victims' Remains for their tireless, ongoing work on behalf of the families of the Disappeared.
"That work will continue to have our full support with the aim of ensuring that the remains of the other victims will be located. Anybody with any information that can assist in that task should bring it forward without delay."
Investigations into the remaining disappeared victims - Joe Lynskey, Columba McVeigh and Robert Nairac - are continuing.
There were 16 people who 'disappeared' during The Troubles in Northern Ireland.
The Provisional IRA admitted responsibility for 13 of the 16, while one was admitted by the INLA. No attribution has been given to the remaining two.
The ICLVR operates a freephone number - 00800-5558-5500 - and a PO Box address at PO Box 10827, Dublin 2, Ireland to receive information in confidence.