I will look at the aftermath of the war in Japan and Germany because, of course, the aftermath of a war is going to be different for the winners like France and Britain than for the losers like Japan and Germany.
There are a few major similarities between the aftermaths in these two countries. First, they were both devastated by the war and would have to spend a fairly long time rebuilding. Second, they were both occupied by the militaries of one or more of the powers that defeated them in the war. Third, they both (at least in the case of West Germany) soon became allies of the powers that defeated them.
The major difference between the two is that Germany was divided as a country while Japan remained whole. A second important difference is that the US did much more to completely remake the Japanese system of government than it did in Germany. The US occupation of Japan was run by one person (Douglas MacArthur) who undertook the project of giving Japan a new constitution with provisions like land reform, women's rights, and pacifism that would completely change Japan. A smaller difference is that the pre-war "leader" of Japan, Emperor Hirohito, was retained as a figurehead so there was some greater continuity (at least on a cosmetic level) than there was in Germany.