Thank You for opening a window of discussion on this issue.
In France, a dress similar to a burkini which does not dissimulate the face, is not against the Law. Regardeless if you chose to take a sea bath with it, or not. Indeed, it never happened for a lady to be fined with a Saree or a Boubou ensemble !
Not so long ago, my grand mother was always dressed in a decent way when she took a sea bath (including headdress, shoes and stockings, of course).
In many countries -and in France too- there is the widely disseminated feeling among many people that the Book of a specific religion is at the root of terrorism (Of course, these people never read our Old Book !). But it is the reason why they consider that a burkini at the beach necessarily is ostentatious and is an obvious provocation. It is the reason why the police force are being asked to stop a public nuisance. And the burkini is not allowed on several beaches for that reason.
Is it democratic ? One can ask. Indeed, there are many Judeo-Christian traditional dresses, or sikh headdress, which are not questionned at all. But the politicians do take into account the people who gave them a job.