Some of France's wealthiest people have called on the government to tackle its deficit by raising taxes - on the rich.
Sixteen executives, including Europe's richest woman, the L'Oreal heiress Liliane Bettencourt, offered in an open letter to pay a "special contribution" in a spirit of "solidarity".
Later the government is due to announce tighter fiscal measures as it seeks to reassure markets and curb the deficit.
They are expected to include a special tax on the super-rich.
Before the announcement, expected on Wednesday evening, a letter appeared on the website of the French magazine Le Nouvel Observateur.
It was signed by some of France's most high-profile chief executives, including Christophe de Margerie of oil firm Total, Frederic Oudea of bank Societe Generale, and Air France's Jean-Cyril Spinetta.
They said: "We, the presidents and leaders of industry, businessmen and women, bankers and wealthy citizens would like the richest people to have to pay a 'special contribution'."
They said they had benefited from the French system and that: "When the public finances deficit and the prospects of a worsening state debt threaten the future of France and Europe and when the government is asking everybody for solidarity, it seems necessary for us to contribute."
They warned, however, that the contribution should not be so severe that it would provoke an exodus of the rich or increased tax avoidance.
The move follows a call by US billionaire investor Warren Buffett for higher taxes on the American ultra-rich.
The French government has already said it is working on a special tax on those earning more than 1m euros (£900,000) a year.
The measures are expected to be part of a new package aimed at cutting up to 14bn euros from the budget deficit over the next two years.
It is not clear exactly what form they will take, but they are expected to include a reduction in tax breaks and increased taxes on big companies.
The government has been forced to act after recent fears that France's AAA credit rating could be downgraded.
France plans to trim its public deficit to 5.7 % this year, 4.6 % next year and 3% in 2013.