The hero of “A Prophet, ” Malik El Djebena (Tahar Rahim), is nineteen at the outset, a blank slate of a boy, just starting a French prison sentence of six years.

So far, for pragmatic rather than ideological reasons, the French state has bailed out just one troubled bank: Dexia, a small Franco-Belgian institution.

Yet Paris has many advantages: a large number of international Banks, from BNP-Paribas to credit Agricole; more international companies than Frankfurt; and easy access to regulators.