Tunisians, can someone explain to me the situation about subsaharan immigrants?

Hey there! I’m Algerian! I’ve been hearing a lot of racism towards black people and when I asked about it I was told that Tunisia was in a crisis and that the black people were trying to colonize North Africa, so on and so forth. I’ve heard stories about them breaking into people’s homes and killing them, too. I’m really confused. Can someone explain what’s going on?