Christian Noyer, the governor of Banque de France, on Tuesday said central banks must only intervene in markets in exceptional circumstances.

At a conference in Paris, Noyer said: "Central banks require efficient markets to fulfil their mandates. In some cases this can lead to massive direct interventions in markets but these interventions must remain exceptional."

Noyer said the recent active presence of almost all central banks in a wide range of market segments should not give the impression