"Mr. Nicolas Sarkozy and Mrs. Carla Bruni-Sarkozy cannot accept that remarks made in private were recorded and published without their consent," lawyers Thierry Herzog and Richard Malka said in a statement.

"[They] have decided to prosecute, through an emergency proceeding soon to be filed with the Paris Grand Instance Court, the recording and publication of their conversations," they said.

Excerpts of the tapes were published this week in satirical weekly Le Canard Enchaine and news site Atlantico.fr. The transcripts were of conversations between Sarkozy and his aides that his former advisor Patrick Buisson secretly recorded from 2007-2012.

In the published excerpts Sarkozy is heard discussing his electoral strategy and his wife, Carla Bruni, is recorded joking about how she had to put her modeling career to the side while she was France's first lady.

Critics say the move will fuel speculation that the tapes may contain something more serious that could put the breaks on a possible presidential bid for Sarkozy in 2017. He was defeated by President Francois Hollande two years ago.

On Tuesday, Buisson's lawyer, Gilles-William Goldnadel, said his client had made the recordings for historical research purposes and had not intended that they be made public.

Buisson made the recordings using a device in his pocket and later uploaded to his computer. He maintains the device had been stolen and that he would file a theft complaint.

Breach of privacy in France carries a penalty of up to one year in prison and 45,000 euros ($61,000) in fines.

hc/dr (AFP, AP, dpa)