The French prime minister says New Caledonia's independence referendum is a challenge which is not without risk.
Edouard Philippe made the comment in the French National Assembly which is about to adopt a change to the electoral law defining the restricted referendum roll.
Mr Philippe has appealed to everybody to safeguard what has been attained during 30 years of peace.
He said asking voters whether they were for, or against full sovereignty bears the risk of causing divisions.
And he said more than elsewhere this was dangerous.
Therefore, he said, it is urgent to be reminded of what unites New Caledonia and to protect what has been achieved.
Several assembly members have expressed concern over what will happen the day after the vote which is widely expected to be held on 4 November.