KEY POINTS:
As political honeymoons go, it had a good run. For more than four months, TV footage of meetings between French President Nicolas Sarkozy and German Chancellor Angela Merkel transmitted the traditional, soothing picture: the confident leaders of Europe's two largest economies greeting each other with warm handshakes and hugs, with on-camera chitchat that varied from light to businesslike.
Here were two leaders eager to reassure each other and their European partners that the destinies of France and Germany were intertwined, in a special relationship that was blossoming once more.
A new generation of centre-right leaders - one the daughter of a pastor from former East Germany, the other the son of a Hungarian immigrant - had taken the helm of continental Europe's two biggest economies and all seemed renewed and fresh.
For two countries which fought three wars in the space of 70 years, the Franco-German relationship has always been critical to Europe's political stability and prosperity. Since the end of World War II, successive German and French governments joined to forge the European Union, the introduction of a single economic market and the creation of the single European currency. When ties between a French President and a German Chancellor are on song, Europe hums along.
Now, though, darker rumours are starting to emerge about the Sarkozy-Merkel relationship. It appears that away from the photo-ops, Merkel and Sarkozy are tense, often moody, with sometimes starkly conflicting views as to which direction European integration should take.
Firstly, the personal chemistry is not in sync. Reserved yet steely, Merkel is uncomfortable with Sarkozy's familiar way of kissing and hugging her. The French daily Le Figaro reported that Merkel is irritated at Sarkozy's "rough and ready" manner. For his part, the hyper-active, headline-obsessed President seems disgruntled that the usual combination of bullying and threats that brings results at home doesn't work in Berlin.
The German daily Rheinische Post published comments from members of Sarkozy's UMP party that Merkel is "increasingly getting on his nerves". The paper warned of a "deep crisis" between the two leaders.
Earlier this month, following a bilateral meeting in Meseberg outside Berlin, Sarkozy admitted that talks with Merkel had become "very frank", diplomatic jargon for angry.
"The differences in style have been obvious to everybody," said Ulrike Guerot of the European Council on Foreign Relations. "Alot of people are surprised with how pushy Sarkozy has been with Merkel."
On the matter of substance, though, the situation is arguably worse. Merkel, who has got to grips with Germany's budget problems, has an acid view of France's chronic deficit. Sarkozy, meanwhile, bucks at the independence of the European Central Bank, the master of the eurozone's interest rates.
In July, at a meeting of EU finance ministers in Brussels, German Finance Minister Peer Steinbruck accused the French President of "giving fiscal handouts to voters" instead of keeping his European budgetary pledges, a remark that apparently incensed Sarkozy. "How dare you speak to me in that tone," Sarkozy replied, and was later furious with Merkel for not reprimanding Steinbruck as he requested.
With the euro surging against the dollar, Sarkozy, meanwhile, has been leading a charge for lower euro interest rates to help French exports.
He has called for the status of the European Central Bank, whose independence is spelt out in the Treaty of Maastricht, to be reviewed. Last week, he even claimed the ECB had helped "speculators" and neglected "entrepreneurs" after it pumped billions of euros into the banking system during the financial market turmoil while leaving interest rates unchanged because of its focus on fighting inflation.
Merkel has reacted bluntly to this agitation, for Germany gave up its sacred Deutschemark in exchange for the euro only after getting guarantees that the ECB would be modelled on the lines of the Bundesbank.
"The independence of the European Central Bank is the alpha and omega," Merkel said in July. "And that is why Germany will not budge on this." Last week, she again backed the ECB and its president, Jean-Claude Trichet. "The whole Government including myself believes in the independence of the ECB," she said.
On foreign policy, officials in Berlin privately accuse Sarkozy of grandstanding, of claiming credit for initiatives whose groundwork was laid by Germany, such as the agreement on the new European treaty outline and the release of Bulgarian medics imprisoned in Libya. The release came during Germany's presidency of the EU and, officials claim, followed intensive negotiations between the German and Libyan Foreign Ministries.
Then at a joint news conference after the Meseberg meeting, Sarkozy urged Germany to follow France's example of relying on nuclear power. Merkel's left-right coalition is torn on the issue of nuclear power and although Merkel is in favour of a nuclear power option, the coalition agreement calls for a phasing out of some nuclear reactors.
And there's the rub. Merkel is nursing a coalition that requires constant consultation while Sarkozy scored a healthy win and his centre-right UMP party gained a clear parliamentary victory. His is a one-man-show, hers is one that needs careful handling.
"There is real annoyance, although I wouldn't use the word crisis," said Henrik Uterwedde, of the German-French Institute in Ludwigsburg. "But it's not peanuts and it should ring alarm bells."
FRANCO-GERMAN RELATIONS NOT ALWAYS HUGS AND KISSES
Socialist French President Francois Mitterrand and conservative German Chancellor Helmut Kohl put relations on a new path in 1984 when the two clasped hands at Verdun cemetery, but the relationship soured after the fall of the Berlin Wall when Mitterrand tried to slow down the unification of Germany.
Mitterrand's successor, the conservative Jacques Chirac, backed Helmut Kohl in the 1997 election, which saw Social Democrat Gerhard Schroeder win power.
Chirac and Schroeder argued over EU voting rights, and it took several years for the French to grasp the significance of a German government seeking a more assertive role on the European stage. In the 2002 German elections Chirac backed Schroeder's opponent Edmund Stoiber.
The Franco-German motor sputtered back to life after the two countries joined in criticism of the American war in Iraq, in an alliance that became known as "Old Europe".
By the end of 2003, Chirac was representing Schroeder at an EU summit - an initiative that, these days, seems out of the question.
