You're indeed wrong about Germany, the different attachments don't follow the iron curtain at all. Both west-and east Germany have regions with different attachment color.

Most of the regions with a strong regional attachment seem to correspond to the larger independent states before German unification in the 19th century: https://en.wikipedia.org/wiki/Unification_of_Germany. Mecklenburg, Wurttemberg, Bayern and Upper Saxony are all 4 recognizable on the map of the op. The bit below Denmark was ruled in a personal union by the Danish monarch before the unification wars.

France tried their best to split Saarland off from Germany several times, which might explain their strong regional attachment.