Russian media has reported that members of the Russian legislature have claimed that Germany's reunification was in fact an "annexation" of East Germany by the West and thus they have no right to criticize Russia's annexation of Crimea.
Госдума разберется с аннексией Восточной Германии
Комитет по международным делам рассмотрит вопрос об «аннексии Германской Демократической Республики Федеративной Республикой Германия в 1989 году»
I wonder to what extent this is true.
According to Max Planck Encyclopedia of Public International Law,
Annexation is the forcible acquisition of a state's territory by another state.
So, did East Germany consent to the unification or was it incorporated by force or international pressure?