These days, the only sweet music serenading President Francois Mitterrand is being played courtesy of his ideological opposites at the Reagan White House. At home, Socialist Mitterrand hears mostly angry cries about his economic austerity program from disgruntled citizens marching down the boulevards - truck drivers, coal miners, civil servants, and other groups of his core constituency.
Before his current trip to the United States, he read a history of France from 1815 to 1830. His aides say the choice, a study of the constitutional monarchy following the upheavals of the revolution and Napoleon, was designed to give him clues on how others tried to create stability after periods of upheaval.
The Socialists took a beating in last year's municipal elections and the President's popularity recently dropped to an all-time low 31 percent approval rating.
In Washington, though, American conservatives are hailing the French President for his tough, anti-Soviet foreign policy. American bankers also salute Mitterrand for the stiff, market-oriented austerity he has applied to the economy.
The contrast is striking - and it is perhaps the best insight into Mitterrand's present political predicament and how he plans to turn his fortunes around.
As the first leftist president in a quarter century, Mitterrand was elected in 1981 promising radical reforms. In a whirlwind first year, he seemed to deliver. The guillotine fell silent, taxes were raised on the rich, work-sharing was introduced, and, above all, much of the nation's industry was nationalized.
But today all this looks far from revolutionary. Some reforms merely followed old traditions, few actually challenged custom. Anti-Socialist economist Francois de Closets notes, for example, that the nationalizations merely formalized already-prevalent state direction of the economy. Taxes on the wealthy were raised, but not the low inheritance tax. As a result, de Closets says the French practice of handing down wealth generation to generation continues unabated.
''Under Mitterrand, there has been more continuity than change,'' conservative journalist Alain Duhamel agrees.
Cynically put, the only tidal wave these observers believe the Socialists have helped produce is an intellectual one - against Socialist ideas. Mitterrand's anti-Soviet position has further worsened the image here of both Marxism and Moscow.
The best-seller list reflects this change. Since Mitterrand came to power, the most popular books here are tomes dedicated to neo-liberalism. One book even extols America's ''conservative revolution.''
''Before Mitterrand, the left dominated the battle of ideas,'' Duhamel says. ''Now the conservatives do.''
Economic necessity converted the Socialists themselves. With the economy reeling from a huge trade deficit, double-digit inflation, and three embarrassing devaluations, Mitterrand reversed his original expansionary policies, cutting the government's budget deficit and raising taxes. His conservative predecessor, Valery Giscard d'Estaing, had executed the same policy.
In foreign policy, Mitterrand made a similar shift. Coming to office on an antimilitarist, anticolonialist, and antiinterventionist platform, he pushed for the installation of Pershing II and cruise missiles in Europe and sent troops to two former French colonies, Lebanon and Chad. ''France remains and will remain faithful to its history and commitments,'' he explains.
While this foreign policy has received wide support in the country, the domestic belt-tightening policies have not. Any policy that forced wages down while swelling unemployment to 9 percent does not please the public - even if it may eventually put the economy right.
But the present discontent runs even deeper. It reflects a sense of betrayal. Wide segments of the population who expected to profit from Socialist benevolence are now suffering. Miners who were promised that France needed to produce more coal are facing pit shutdowns. Civil servants who expected generous wage increases face cuts in living standards.
These are the groups who have been demonstrating in recent weeks. Mitterrand has not budged yet under their pressure. But springtime is approaching, and despite the beauty of Paris in bloom, the season is traditionally the time of strikes and street protests. Mitterrand himself is said to expect a ''paroxysm'' of troubles that will test his mettle as a conciliator.
Faced with this peril, any political leader might be expected to be showing signs of nervousness. So far, Mitterrand has not. Although parliamentary elections loom in two years, the President still has four years left in his term , and he repeatedly tells visiters that this ''duration'' will carry him through.
He may be right. Thanks to austerity, the nation's trade deficit has been brought under control. The franc is holding steady. Inflation is still running at about 9 percent, but that is down considerably.
By next year, Mitterrand predicts, the worst of the recession will have passed. Then, as the breezes of the US recovery cross the Atlantic, he will be able to reflate the economy in time for the legislative elections of 1986.