Paris and Brussels have both been officially "smoke-free-indoors" for several years now and, except for an ocaissional crusty old man, it seems to work 98% of the time.
The worst thing about Frenchie J. Citizen-smoker is that he believes standing directly in the doorway, with just his hand outside the door, constitutes "smoking outside". (This is true for both public and service entrances.)
The point: Any pilot or mechanic familiar with bernoulli/venturi effects will understand the inevitable, repetitive in-rush of doorway smoke.
In addition, most larger urban department stores now have long lines of power-puffing "shoppers" along the external facades originally intended for window-shoppers.
The smoker's sidewalks have essentially become giant ashtrays and are nearly impassible due to crowd-pack and smoke.