It's not banned by law, but, especially after what happened to Charlie Hebdo (and it wasn't the first or the last incident like that, however probably most drastic), I'd say people are afraid to publicly say negative things about Islam, because the threat to their lives is very real. So, while we might have freedom of speech written into the laws and the state per se is not taking it away from us, it's also not protecting it enough from extremists who are against it.