On February 26, the European Court of Justice (ECJ) ruled in the Wächtler case that the German exit tax in its current form violates the Agreement on the Free Movement of Persons (AFMP) between Switzerland and the EU (ECJ, 26 February 2019, ECLI:EU:C:2019:138, Wächtler case) and fully endorsed the Advocate General's pleading.
This means in particular that an unrestricted, interest-free deferment of payment must be granted by Germany also in relation to Switzerland.
However, the ECJ allows the German tax authorities to make this deferment dependent on a security deposit (e.g. a bank guarantee) in deviation from the EU/EEA cases (cf. section 6 para. 5 sentence 1 AStG).
This applies at least to taxpayers who establish themselves in Switzerland in order to exercise an independent activity there. There is no certainty yet, if the AFMP also protects taxpayers in different situations, e.g. when they are moving to Switzerland after their retirement and not for working / business reasons.
It will be interesting to see how the German legislator reacts. At the first glance, there seem to be different options:
Possibly, Switzerland will be included in the previous regulation on EU/EEA cases...