A tactical strike is likely to be dictated by the military situation at hand. Many of these locations (Leningrad, Moscow, Warsaw) are going to be important in a strategic attack, but they would probably not be the first targets.
If we are saying that the United States is likely to be the one that resorts to tactical nuclear weapons first, it depends on the situation on the ground. Berlin is likely to fall without any nuclear shots.
The Soviet Plan would be to punch through the Fulda Gap and move towards the Rhine River. At this time, France has no nuclear arsenal, and the UK's nuclear program is just getting started. So there is no inherent assumption that NATO would deploy tactical nukes short of the Rhine; they might deploy them over France.
So the questions of when the US resorts to tactical nukes is up in the air. The first shots will almost certainly be over advancing Soviet Troops; probably in Germany/France, perhaps outside Paris or something.
The Soviets will then respond by hitting defending NATO troops; it might decide to escalate the exchange, but either way, at a minimum, it nukes NATO forces in retaliation.
Now the positions on the ground are important. It makes some difference in terms of range on whether the Soviets are outside Paris or Berlin when they try to launch nuclear attacks. I'm unsure, and very skeptical, that the Soviet Union would hit something like Bonn or Copenhagen if they're occupying it. Not that it would not be something to destroy, but because it may kill the garrisons that occupy those areas.
Eventually, one side is going to decide to go beyond tactical nuclear weapons.
The Soviet Union's nuclear arsenal is very limited at this point, and they are going to have to consider hitting military targets for the simple sake of trying to stop nuclear hits against their country by other means. The Soviets have little ability to hit the United States at this time, so unless they are out to bleed Europe, their nuclear offensive (or at least their penultimate one) is against military targets. That said, a nation's capitol definitely counts as a military target, and many bases are close to major cities; finally, Soviet weapons are inaccurate and so rely on heavier payloads.
The United States did not consider the idea of attacking enemy nuclear weapons at this time, so it's likely to go for everything. Hungary, which had attempt to throw off its Soviet Overlords in 1954, would be mostly spared, occupied territory would be spared if possible, and as I understand it, so would Yugoslavia.
It is possible that the US attack breaks the Soviet chain of command; if it does not, the Soviets will throw all caution to the wind and start hitting cities in Europe--but this may be a decision too late, as the US attack is going to be far more massive than their own.
anish nstitute of International Studies)