French Polynesia's pro-independence Tavini Huiraatira Party has denounced a change to the French constitution which now says that regional languages are part of France's heritage.
The decision was taken by the French Congress which narrowly approved the provision of declaring 75 languages spoken and used on French-controlled territory part of the nation's heritage.
A Tavini statement says French Polynesia's languages now no longer belong to a people but to the history of France.
It says this amounts to a colonialist attitude which will foster hatred.
The constitutional change was approved by the three French Polynesian members of the French Congress which includes both houses of parliament.
One of them, Gaston Flosse, says the official recognition of Tahitian allows assembly members to use the language.
Two years ago, the French supreme court ruled that Tahitian was not allowed to be used in assembly debates.
As the ruling was being defied, the French supreme court annulled two territorial laws because Tahitian was used during the preceding debate.