I think it is the same for german police. I.e. you at least have to shot in the air once and call out "stop or i will shoot you!".
Obviously, this is not necessary if the life of the officer or someone else is at risk.
People made fun of this, because when criminal has a gun, he won't be shooting in the air 3 times, nor targeting policeman legs, so law was changed to be less strict about cops shooting.
But we still have strict regulations about "allowed defence". For example courts judged a few times, that man that shot burglar with legal gun he had in his house was guilty of "overstepping allowed defence", because burglar only had knife. It's ridiculus IMHO.
Still - I've never heard or seen a real gun or knife fight in my life, and neither had anybody I know (or at least they had not told me about that). I think it's general tendency, that gun crimes and homicides in general are much less frequent in Europe.