There is one party with known ties to Russia since a t least a decade, that is also known to be openly fascist in some states and a suspect of being far right extremist in all states and the federal level.
But instead of working to ban the AfD the current government is reluctant to initiate the process with the constitutional court. Meanwhile many of the political goals of the AfD are being put into laws by the current government coalition of supposed social democrats, greens and liberals, trying to "win back" AfD voters. Instead all this does is normalize their fascist positions further. Meanwhile the supposed conservatives engage in far right populism, often exceeding what the AfD said 5-10 years ago
The fascists aren't winning in Germany because of their strength, but because of the weakness and lack of resolve to fight them, as well as willingness to cooperate in some parts of the supposed democratic parties.
Meanwhile the former left ist pulverized and a new party, BSW, emerged, that is also heavily pro Putin as well as nationalist, but more social in their rethoric. How much of that social rethoric actually holds true might become known soon, as there is two German states, Brandenburg and Thuringen, where a majority coalition without AfD or BSW is not possible.