French President Jacques Chirac has called for a Yes vote in next month's referendum on autonomy in Corsica, as the government attempts to end years of separatist violence.
Chirac: Vast majority of Corsicans want to stay French
In an interview with the local Corse-Matin newspaper, Mr Chirac said the vote was Corsicans' best opportunity to show their attachment to France.
The island's 190,000 voters go to the polls on 6 July to decide whether to back the government's plan to simplify the regional administration and give it greater powers.
But the No campaign has been gaining ground among opponents of self-determination.
They are concerned that separatists - who represent only about 20% of the population - are urging a Yes vote as a first step towards independence.
I want to tell Corsicans that this vote is a chance for Corsica - I urge Corsicans to seize it - it's the best way to re-affirm your attachment to France and the republic
But Mr Chirac said a No vote would play into the hands of the separatists.
"To say No just because some [nationalists] say Yes - that makes no sense," he said.
"That would make them masters of the game... I know that the vast majority of Corsicans want to stay French. It would be incomprehensible if, at the moment they are asked to confirm it, they fail to."
The new plan would merge three separate bodies into a single regional assembly, and devolve some control of energy, transport and regional aid policy.
It follows constitutional amendments approved in March under which France's 22 regions and 96 departments can choose greater autonomy.
Corsica has been plagued by decades of low-level violence by separatist militants.
Last October, 14 bombs exploded across the island ahead of a visit by Interior Minister Nicolas Sarkozy.