New Caledonian leaders have agreed on the make-up of the electoral roll for those eligible to vote in the independence referendum due by 2018.
The breakthrough came during 12 hours of negotiations in Paris at a special meeting chaired by the French prime minister, Manuel Valls.
The anti-independence side secured concessions from the rival pro-independence camp, which agreed to broaden the terms for automatic inscription on the roll.
The previous bill, which had been put forward by the government, limited automatic registration to indigenous people and those who had voted in the 1998 referendum on the Noumea Accord, which is the decolonisation roadmap being applied now.
The French Senate is due to debate the amendment at the end of the month as part of the law change needed for the referendum vote.
The Paris meeting also agreed to change the commission vetting a separate electoral roll used for provincial elections that determine the make-up of the Congress and the government.
Both rolls have been at the heart of prolonged disputes which in April led to a mass rally in Noumea against independence from France.
The strong opposition of the loyalists against the French government's original roll stance prompted Paris to convene this week's first ever extraordinary meeting of the signatories of the Noumea Accord.