New Caledonia's Congress has decided to set up a commission of inquiry into this week's sacking of the head of the tax administration, Stephanie Boiteux.
She was dismissed by the President, Harold Martin, for expressing her view during a committee meeting on tax reforms last month when she had been asked to be silent.
Mr Martin says she had to be disciplined for breaching rules pertaining to her role.
Ms Boiteux has taken her case to court.
The Congress has opened the probe on behest of the Caledonia Together Party, saying she had shown perfect integrity and a sense of the common interest.
The tax debate was part of the resolution of a 12-day general strike last month aimed at lowering the high cost of living.