Another attempt to extradite Ian Bailey to France could be made early next year, according to a solicitor for Sophie Toscan du Plantier's family.
The French authorities have failed three times to get him sent there, over the murder of the filmmaker in west Cork in 1996.
Mr Bailey was convicted in his absence in Paris two years ago, but has never been charged here.
Solicitor Alain Spilliaert says the European Commission has raised concerns about Ireland's compliance with European Arrest Warrants.
"Because of this dialogue between Ireland the European Commission, Ireland has corrected too slow.
"Then there is an opportunity for the French prosecutor to issue a new European arrest warrant, and start again the whole process before the Irish courts."