Hours before a key summit meeting in Brussels, Manuel Valls said there could be 'no taboo subject' in talks to keep Greece within the eurozone.
Finance minister Michel Sapin insisted there would be no 'Grexit' despite collapse of latest talks and a referendum in Greece.
Emmanuel Macron and Sigmar Gabriel publish a joint op-ed calling for a common treasury for the eurozone with power to set taxation policies.
French economic growth in first quarter was an unforecast 0.6%, the highest in eurozone, while German growth fell and Greek economy shrank.
France was said to be the main drag on growth in key index of private sector activity in the single currency bloc as activity in German also slows.
Since 1999, France has a more impressive record on economic growth, productivity and financial sector stability than many eurozone peers.
John Lewis managing director told meeting: 'I have never been to a country more ill at ease - nothing works and nobody cares about it.'
While the collapse of the French government highlighted policy divisions and personal ambitions, the cause is the crisis in the eurozone.
The German chancellor said eurozone's faltering growth was due to its inability to punish 'those countries that break the rules'.
Just before French government members left on their two-week summer holidays earlier this month, they met with President François Hollande for a confidential seminar in which they were presented with an alarming set of economic figures and forecasts that promise dark times when they return to work on August 18th. The deflationist spiral into which Europe is being drawn threatens to destroy all hope of France recovering growth, reducing already chronic unemployment, or of straightening its public accounts. Just as worryingly, the government appears divided and dithering over the policy direction to be adopted to avoid what some business leaders predict could become a new and catastrophic crisis by 2015. Mediapart’s economic and business affairs correspondent Martine Orange reports.
Manuel Valls says the eurozone's economic policies are not effective, adding that there will be 'difficult' months ahead for Europe.
French business activity contracted further in June, stoking fears that Europe's attempts to kickstart lasting economic growth is losing momentum.
Analysts fear a weak manufacturing sector in France could hold back output across the rest of the Eurozone.
Unexpected second-quarter economic growth of 0.5% in France, 0.7% in Germany sees eurozone grow overall 0.3%, ending18-month recession.
Billionaire boss of CQS writes to investors warning French economic and social unrest that could take the eurozone’s troubles 'to a higher plane'.