The writers say the violence sparked by the publication of cartoons satirising the Prophet Muhammad shows the need to fight for secular values and freedom.
The statement is published in Charlie Hebdo, one of several European papers to reprint the caricatures.
The images, first published in Denmark, have angered Muslims across the world.
One showed the Prophet Muhammad, whose depiction is banned in Islam, as a terrorist bomber.
Many newspapers defended their decision to reprint the cartoons on the grounds of freedom of expression.
‘Global threat’
Almost all of those who have signed the statement have experienced difficulties with Islamic militancy first-hand, says the BBC’s Caroline Wyatt in Paris.
They include Dutch MP and filmmaker Ayaan Hirsi Ali and exiled Bangladeshi writer Taslima Nasreen.