President Nicolas Sarkozy appointed Pepy to run the state-owned enterprise on 27 February 2008 for a term of five years.

He is a graduate of Sciences Po and a former alumnus of École nationale d'administration, in the Louise Michel year (1984).

In 1995, Pepy was appointed deputy chief executive officer of the Sofres group with special responsibility for business development.

He instituted a new low fares policy designed to boost train occupancy rates using "yield management" flexible pricing techniques.

Anne-Marie Idrac, chairman in the last 20 months of the term begun by Louis Gallois (July 2006- February 2008), confirmed him in this position.