Well i would be a large mistake to think that a SPD government in Germany will tolerate infaltion or things like that.
The ordinary German is highly against it including more bail outs for the so called "Club Méditerranée" etc...
It's true that SPD will never accept high inflation - but they are much more likely to accept higher inflation, IMHO. With an inflation rate of, say, 5% p.a., the unions can regularly get through raises of 5% to 6% and SPD can increase social benefits by 4% annually without increasing state expenses in real terms. All that looks good on paper but naturally isn't any better than a raise of 2 to 3% when inflation is 2%.
It's the savers who will suffer, thus typically elderly people and people with money - CDU people. As a consequence, a higher inflation regime will be not that bad for SPD and unions but very bad for CDU IMHO.
That may, however, be superseded by the effect of inflation on the progressive income tax regime. Inflation implies "secret" tax increases in that regime, and both sides of the political spectrum like the idea of more money without increasing taxes. If high inflation comes hand in hand with good economic development, this may be the dominant effect.
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Now for the German-French axis: France often lived under cohabitation, thus the respective other side was at the table as well with the French, and in Germany you mostly had a similar situation with the Bundesrat under the non-governmental majority. Both systems of governance rarely provide the chance of one political side clearly dominating policy for a long term.
Now for "Hollandel", Merkel won't change her position very soon. Hollande, on the other side, will face the problem that most leftist ideas cost money. Money he doesn't have. Actually, even Germany doesn't have that money, even if many in Europe think so (and part of the reason Germany has more money is that Germany already enacted reforms that it now requires the other states to repeat). Granted, they could (and should) increase taxes on capital gains (without killing off private retirement saving - that's not as easy as it seems). And they could increase top taxes (Although that 75% goal of Hollande is bullshit. Anybody who earns that much money to be subject to that tax could also work from London or Zurich or Shanghai). And they should try to tax the big actors on the financial markets (without having private pension savers carry the big load - which is also not as easy as it seems). But I doubt that we'll find the billions of money that way to preserve our social systems the way they are.