Prosecutors in Germany say they have opened a formal investigation into the French far-right politician, Jean Marie le Pen, for comments he made about the Holocaust.

They say they want to question him over remarks he made in Munich last year describing the gas chambers at Nazi death camps as a detail in the history of the Second World War.

The move follows the decision by the European Parliament to lift his immunity from prosecution.

Under German law he could face up to five years in prison if convicted of trivialising the significance of the Holocaust.

Mr Le Pen denies his remarks belittled the Holocaust.