I do not know enough about other cities but in London one can only walk a few steps and a CCTV is at work. Apparently France is now going to take a leaf out of our book and increase security as apparently they have been rather lax.
I have no objections to high security wherever I go and I agree it is good to hear that it is effective at airports too, I was working in central London during the 7/7 attacks and it was scary- being a case of "there but for the grace of God" etc.
I always felt that never should the b*****s get us down and I continued as usual but I was more aware of what was going on around me when on a tube etc.