France's top legal authority has approved a law banning full-face veils in public, the last hurdle for the ban, which aims to protect women's rights but has been criticised as stigmatising Muslims.

The Constitutional Council, which had previously warned that banning the veil may be unconstitutional, said it approved the version of the bill, which has been passed by both Houses of Parliament, after a final review.

It judged however that the ban, due to enter force early next year, would be unenforceable in public places of worship, where it may violate religious freedoms.

"The ban on covering the face in public places cannot constrain the practice of religious freedom in places of worship that are open to the public," the council said in its judgement.