Former Bank of France chiefs Michel Camdessus, Jacques de Larosiere and Jean-Claude Trichet sent a support letter to Villeroy de Galhau on Sept. 17 that was seen by Les Echos.

In the letter they wrote: "We do not see anything preventing you, subject to parliament's approval, from taking on - with full competence and independence and after a mixed (professional) background - this essential mission"

The letter was sent after more than 140 economists protested against the appointment of the former banker - rather than a senior civil servant - to head the Bank of France, saying it could raise conflict of interest issues.

The economists, mostly academics, had written in Le Monde newspaper that Francois Villeroy de Galhau was an excellent expert on the banking sector, but that his background risked jeopardising his independence at the central bank.

Villeroy de Galhau, 56, is a former finance ministry official who was one of two chief operating officers at BNP Paribas, the euro zone's biggest bank by assets, until he stood down in April to write a government report on financing corporate investment.

President Francois Hollande named Villeroy de Galhau earlier this month to run the Bank of France, subject to lawmakers' approval, after current governor Christian Noyer retires at the end of next month.

(Reporting by Dominique Vidalon; Editing by Tom Heneghan)