Germany's growing economic dominance as France struggles to recover, coupled with an ideological split between belt-tightening and growth fuelled by public spending, have only fed a growing sense of alienation between the two neighbours.
"Relations are cool," said Claire Demesmay, an analyst on Franco-German ties at the German Council on Foreign Relations.
"In terms of economic performance, the gap is widening and suddenly the analyses differ a bit more."
The Franco-German member of the European Parliament for the Greens, Daniel Cohn-Bendit, can see both sides of the divide.
"Merkel is still very active in Europe, she gets involved a lot behind the scenes, while Hollande is very cautious," he told AFP.
"Merkel determines the balance of power, Hollande evaluates it."
But Cohn-Bendit says talk of an all-time low in relations across the Rhine can only be seen as exaggerated.
"Of course, the Franco-German motor occasionally misfires, but that's always been the case," he said, noting that Hollande's predecessor Nicolas Sarkozy and Merkel famously had trouble finding common ground before they forged their "Merkozy" pragmatic partnership.
But another breakdown came Friday when Hollande's Socialist Party in a draft document branded Merkel an "austerity chancellor" and accused her of "selfish intransigence".
The offending passages were later excised, but not before causing another diplomatic eruption at the heart of the European Union.
The German government sought to stamp out the sparks, but Merkel's conservative Christian Democratic Union (CDU) leapt on the document as an opportunity five months out from Germany's September 22 general election.
In a scathing statement, the CDU's deputy parliamentary group leader said the manifesto showed "the considerable desperation" of the Socialists, who, a year after winning power, had found "no convincing answers" to the country's economic and fiscal problems.
"The leftwing government cannot deflect from the fact that France needs far-reaching structural reforms," Andreas Schockenhoff said.
After campaigning on an anti-Merkel platform of reviving the economy and the labour market by stimulating growth – hopes that have been dashed over the last 12 months – Hollande has turned to a policy of fiscal rigour and backing for business that has antagonised his leftist base.
This about-face has secretly pleased Berlin, just as it takes pains not to drive Paris too far out of its orbit in an election year.
"Merkel has only one fear – that François Hollande publicly says, 'We'll let the deficits slide,' taking the lead of a kind of alliance of southern countries which would end up isolating her in Europe," said a Berlin-based European diplomat.
After Portugal and Spain, now Italy has come forward with new calls for deficit spending to drive growth, which threatens to leave Germany the odd man out.
But Merkel, frequently dubbed the world's most powerful woman despite – or perhaps due to – the controversy she generates in Europe, has an ace up her sleeve.
"Germany's advantage is that it has a position: fiscal responsibility. You either share it or you don't," said European Parliament member Cohn-Bendit.
"With Hollande, you don't know. And both of them are scared stiff about this debate before the German elections," which could see Merkel's party come out on top and still lose its majority with its current partner, the pro-business Free Democrats.
But "betting on the SPD (the chief opposition party, the Social Democrats), as Hollande seems to be doing, is risky," said analyst Demesmay.
Hollande came to Berlin in late 2011, while still a candidate, to rally the SPD to beat Merkel, who for her part campaigned in France for Sarkozy last year.
A former Germany correspondent for French newspaper Le Monde, Luc Rosenzweig, noted that the SPD's current challenger to Merkel, Peer Steinbrueck, was a fiscally conservative centrist.
"He comes from the Gerhard Schroeder school," Rosenzweig told the German daily Frankfurter Allgemeine Zeitung, referring to Merkel's predecessor who introduced sweeping labour-market reforms that revitalised the economy but are blamed for exacerbating inequality.