The 50% score was up about from the 39% who said they backed 'Grexit' in a similar survey a month ago, hinting at a growing frustration with Athens even in France, whose political leaders have been among its supporters.
The latest poll was conducted on Monday, a day after Greek voters delivered a clear 'No' to the latest cash-for-reform offer by Greece's creditors.
No fewer than 75% of those surveyed dismissed the proposition that "austerity policies are the only way out of the economic crisis for Europe", while a small majority (55%) were in favor of restructuring Greek debt.
Despite calls by France's far-right National Front this week for a dissolution of the eurozone, French public support for the single currency was holding up, with 67% opposed to abandoning the euro to return to the French franc.
The Odoxa poll of 1,003 people was carried out by Internet.