PARIS (Reuters) - The police evacuated Paris' Notre Dame Cathedral on Tuesday after a well-known far-right former activist committed suicide by shooting himself in the mouth in front of its main altar, a police source said.

The man, Mr Dominique Venner, 78, is a historian known in France for his far-right political essays.

He carried a letter on his person but made no declaration before shooting himself dead in the mid-afternoon, the source said.

A note posted on his blog dated May 21 slammed a law passed by the Socialist government last week allowing same-sex marriage.

Notre Dame is one of Paris' most-visited tourist attractions.