Prosecutors say the fire at the prayer hall in the capital, Ajaccio, was probably a criminal act. The French Mediterranean island experienced days of anti-Arab riots over Christmas.
The Muslim prayer hall, one of the largest in the Corsican capital, was seriously damaged overnight to Sunday in what prosecutors said was likely to have been a deliberate arson attack.
No one was injured in the fire. Police suspected criminal involvement after discovering that there were two separate sources of fire inside the hall.
"If it is confirmed to be of criminal origin, those responsible must be rapidly identified and brought to justice," said French President Francois Hollande in a statement, adding: "Any anti-religious act must not be tolerated."
The incident echoes an incident in late December, when a Muslim prayer hall was vandalized in anti-immigrant protests that broke out after firemen and police in Ajaccio were ambushed and attacked after having been called to a low-income immigrant neighborhood.
Several acts directed against Muslims occurred in several days of ensuing racial tension, including an attack on a Muslim butcher's shop.
Nationalists won regional elections in Corsica for the first time in December.
Some eight to 10 percent of people living on the Mediterranean island are foreigners, giving it the largest immigrant population in France after the Paris region.
On Saturday, French Interior Minister Bernard Cazeneuve issued a statement vowing "solidarity with the Muslims of Corsica."
Corsica is popular with tourists owing to its fine beaches and spectacular mountain landscape.
tj/rc (Reuters, AFP)