A socialist government, or an organized proletariat and their vanguard party.
Unfortunately the decades of suppressing the left since the Cold War and annexation of the GDR means an organized proletariat and a vanguard party has not emerged in Germany (though there is the DKP), hence the rise of the far-right. A socialist government like the GDR would correctly label these as nazis and would not have let the far-right grow to this point.