Provocative posters showing a woman wearing a face veil with the words stop extremism are being put up across Switzerland.The billboard is part of a campaign by the far-right Swiss People's Party (SVP) to ban face coverings in public.And on Sunday, voters will decide in a binding national referendum.The proposal does not mention Islam directly, and also aims to stop violent street protesters and football hooligans wearing masks.Still, local politicians, media and campaigners have dubbed it the burqa ban.And compounds Switzerland's tense relationship with Islam after citizens voted to ban building any new minarets in 2009.Jean-Luc Addor is a member of parliament and part of the campaign."This (niqab wearing) is something that we find shocking. It is fundamentally in opposition with various values of our civilisation simply because, for us, free people show their faces in all circumstances outside."France banned wearing a full face veil in public in 2011 and Denmark, Austria, the Netherlands, and Bulgaria have full or partial bans on wearing face coverings in public.The numbers in Switzerland are tiny. The University of Lucerne estimates no one in the country actually wears a burqa and only around 30 women wear the niqab.Swiss Muslims have said right-wing parties were using the vote to rally their supporters and demonize them.Ouissem Ben Mustapha-Bennour is a Muslim member of an anti-racist association."We women are fed up, and especially Muslim women. We are always being singled out as if we were submissive women, incapable to think or make our own choices. No, we made our choice, the niqab or the veil. Even if I don't wear the niqab, I also stand up for it, like I stand up for any other woman who chooses to wear or not to wear a garment. It's her choice. We are in Switzerland. We are in a secular country. All of our choices must be respected and not politicized." The government has recommended for voters to pick "no" in Sunday's referendum, but opinion polls suggest most Swiss will back the ban and it will become law.