The newspaper revealed on its website on Monday afternoon that it had received the letter, and its editor-in-chief, Hubert Leclercq, told AFP that a black-and-white postcard contained "the same signature" as that on as previous threats in May and July.

"It contained very clear threats," he underlined.

The police spokesman refused to give any more information regarding the note.

Last year's threats to the 81-year-old queen led to a man with British nationality being interviewed by police but then released.