Why are governments trying to force private banks into taking Greek debt?

Doesn't anyone remember that just a couple of weeks ago people were saying that Greece had to be bailed out because so French banks had so much money invested in Greek debt? It is amazing how these things snowball. Governments get banks to take debt that they don't want. Debt goes bad. More government involvement and more government coercion. From Reuters today:

French banks have agreed to roll over holdings of Greek debt for 30 years, President Nicolas Sarkozy said on Monday, as the Greek government fought to persuade backbench rebels to back a crucial austerity plan to avert bankruptcy.
With financial markets watching the Greek crisis anxiously, Sarkozy told a news conference in Paris that the French authorities had reached an agreement with the banks on a voluntary rollover of maturing bonds.
"We concluded that by stretching out the loans over 30 years, putting (interest rates) at the level of European loans, plus a premium indexed to future Greek growth, that would be a system that each country could find attractive," he said. . . .