i was thinking of a more democratic socialist that in the 30s begins to evolve into a dictatorship.
If you go along these lines, then you won't have a WW2 as we know it. It is probable, that this Germany would see the Soviets as their ally in Europe (as actually the Weimar Republic did for some time and also Hitler from 1939-41).
First of all, think of different alignment in the Spanish Civil War. No German support for Franco, that is for sure. This might even prevent the attempt to take over itself, as Franco had to rely heavily on German transports to get his troops from Spanish-Marocco to the mainland.
Then, before you think of war against major powers, this alternate Germany would first have to deal with the matters rather swiftly "solved" by Hitler in 1938.
Austria would still be propped up by Mussolini. So if Germany tries anything there, they might expect Italian intervention, at least as long as Austria would be conservative-authoritarian as in OTL. If butterflies, German influence or further developments make Austria turn left, Anschluss might again occur. But we might also see an isolated German-Italian-war over Austria. I do not see any foreign intervention in this event, though.
The CSR was from 1935 onwards allied with the Soviet Union. If this occurs OTL would be up for discussion. However, it is possible that a negotiated solution might occur there, federalizing the CSR (turning it into a proper Eastern Switzerland) but not breaking it up.
A socialist Germany, just like the Weimar Republic, would probably concentrate on Poland. Alignment with Moscow can only help there. Without occupying Prague beforehands, maybe even without a Sudeten-Crisis, France and England might hesitate with a DOW when Stalin and Germany partition Poland. This would most probably be different from OTL's 4th partition as this would encompass shrinking Poland to a core which is without the shadow of a doubt Polish and installs a socialist government there. Germany might not even reclaim all of its pre-1914 territory.
After all, probably no WW2 unless a string of crises similar to the Spanish Civil War prop the Capitalist and Socialist nations against each other. Apart from that: German Leftists have their place in the sun, having satisfied most nationalist demands (apart from the fringe-illusions) and can concentrate on interior policies. Stalin feels safe with Poland turned into a buffer, Germany as an ally and a proof that France and England have lost the vigour to act if not extremely provoked. Mussolini will have his hands full with internal trouble after his adventures in Spain and Austria failed - and who knows what butterflies are around in Abbessinya. France and England, well they can live with that situation and the US are isolationist resp. having more of an eye on Asia.