France prohibited the concealment of the face in public space by a law of 2010, drafted without naming any religion but universally understood as directed at the niqab, and Belgium followed with a comparable measure. Similar restrictions have since been enacted in Austria, Denmark, Bulgaria and parts of Switzerland, and in various forms in a number of Muslim majority states for security reasons.
The French law was challenged at the European Court of Human Rights in a case brought by a French Muslim woman, decided in 2014. The Court rejected the government's public safety argument as disproportionate on the evidence, and also rejected the argument based on gender equality, on the ground that a state cannot invoke equality to ban a practice that women defend as their own choice. It nevertheless upheld the law, on a different and much criticised ground: that the state was entitled to protect the conditions of living together, a minimum of open social interaction, as an element of the rights and freedoms of others. Several judges dissented, arguing that living together is too vague a notion to justify a criminal prohibition on religious dress.
Four years later the United Nations Human Rights Committee reached the opposite conclusion on the same kind of law, finding in individual communications against France that the ban violated freedom of religion and was not shown to be necessary or proportionate.
So two international bodies applying comparable guarantees produced opposite answers, and both decisions stand within their own systems. That divergence, rather than the merits of either, is the durable fact.
Enforcement in practice has been uneven, and the numbers of women affected in each country are small, which is itself part of the argument on both sides.