The French Senate has overwhelmingly backed a bill banning the wearing of the full Islamic veil in public.
But the leaders of both parliamentary houses said they had asked a special council to first ensure the measure passes constitutional conditions amid concerns it tramples on religious freedoms.
The Senate voted 246 to 1 in favour of the bill, which has already passed in the lower chamber, the National Assembly. It will need President Nicolas Sarkozy's signature.
Legislative leaders said they wanted the Constitutional Council to examine it.
"This law was the object of long and complex debates," the Senate president, Gerard Larcher, and National Assembly head Bernard Accoyer said in a joint statement explaining their move. They said that they want to be certain there is "no uncertainty" about it conforming to the constitution.
The measure will impact upon less than 2,000 women.
Many Muslims believe the legislation is one more blow to France's second religion, and risks raising the level of Islamophobia in a country where mosques, like synagogues, are sporadic targets of hate.
However, the vast majority behind the measure say it will preserve the nation's singular values, including its secular foundation and a notion of fraternity that is contrary to those who hide their faces.
France would be the first European country to pass such a law though others, notably neighbouring Belgium, are considering laws against face-covering veils.
"Our duty concerning such fundamental principles of our society is to speak with one voice," said justice minister Michele Alliot-Marie, opening a debate ahead of the vote.