(Reuters) -- On arriving for the ceremony at the 18th century palace, Macron, 39, a former investment banker and economy minister, held a private meeting with outgoing Socialist President Francois Hollande on state affairs which included the transfer of access to France's nuclear missile launch codes.

Macron becomes France's youngest post-war leader and the first to be born after 1958 when President Charles de Gaulle put in place the Fifth Republic.

He officially became president when Laurent Fabius, chairman of the constitutional council and a former prime minister, read out the results of the election in which Macron beat far right leader Marine Le Pen.