French presidential hopeful Nicolas Sarkozy courted fresh controversy on Monday by insisting that immigrants granted citizenship in France must accept "your ancestors are the Gauls".

In his latest attempt to woo the far-Right at a public meeting in the northern Paris suburb of Franconville, the outspoken former president, who hopes to be re-elected in 2017, said immigrants must "live like the French", and denounced "extremist political Islam" whose goal was to "provoke the Republic."

"I will be the president of action, I do not accept the 238" victims of attacks in France since January 2015, he added, promising to lead a "merciless war" on Islamist terrorism.

"I will not accept the medieval behaviour that wants men to swim in swimsuits while the women are locked up" in burkinis, he added.