An appeal court in New Caledonia has ordered the immediate release of the USTKE union leader, Gerard Jodar, who was imprisoned last June.
Jodar had been convicted to a one-year prison term for his role in last May's violence at Noumea's domestic airport at the height of a protracted strike at the territory's domestic airline.
His lawyer says the release addresses an abnormal situation which saw her client and other unionists being jailed for union activities while their court sentence was being appealed in Paris.
The incarceration has been used by the union to campaign for changes at the territory's jail which is among the most overcrowded prisons run by France.
Last week, a parliamentary delegation from France visited the Camp Est jail and denounced its poor state.
The French government has said it will address what it calls an unacceptable situation.