Infuriated by insults from councillor Luc Brigato, the president Lucette Taero temporarily handed over the leadership to the vice-president, then descended from her seat to twice slap her adversary then land a punch on him.
Only the intervention of other assembly members and staff managed to separate Taero from her victim, who did his best to keep her at a distance.
The scuffle underlined the bitter rivalry between pro and anti-independence parties in the French overseas territory since Taero's election to the head of the assembly in May 2001.
"This inadmissible conduct is the outcome of a constant degradation of the political climate of Polynesia"
There have been a series of rows over issues including a new rule which limits the speaking time of political groups according to their importance and insults for which Taero was herself condemned by a tribunal.
Both Taero and French Polynesia's long-term president Gaston Flosse belong to the Tahoeraa Huiraatira party, which wants to keep links with France, while the opposition Tavini Huiraatira party demands full independence.
"This inadmissible conduct," said Brigato, is "the outcome of a constant degradation of the political climate of Polynesia where the arrogance and aggressiveness of a single party reigns."
He also said that Flosse would use the incident to ask for the dissolution of the assembly and the holding of new elections.
French Polynesia is halfway between Australia and South America and has around 230,000 inhabitants.