The French prime minister's office has admitted to tipping off prosecutors about possible leaks to the website Mediapart - whose offices police attempted to search on Monday.
It's generated a major row about the journalists' right to keep their sources private - in a case that could prove very embarrassing to the French President.
Elena Casas reports from Paris.

Congo Ebola outbreak kills more than 5,000
Saudi Arabia intercepts and destroys drone in Mecca region
7 dead after torrential rains triggered flash floods in eastern Syria
Six feared dead in helicopter crash in Indian Himalayan state, media report
