The claims sparked instant consternation and denials from the French intelligence community, as the official foreign ministry line has always been that she was an innocent academic with no links to spying.

"She was our representative's contact," said Mr Siramy.

In this capacity she provided reports on domestic politics in the run up to last July's presidential elections and on a nuclear site under construction next to the central town of Isfahan where she was an assistant university teacher, said Mr Siramy.

"She deserves to be recognised as someone who worked very well (for France)," he said.

Anonymous, high-ranking sources in the DGSE broke their traditional silence to deny Mr Siramy's "mendacious claims". "Miss Reiss has never worked for us" in any capacity and was never assigned a code name or number, the sources said. Mr Siramy was already in their sights for recently publishing a revealing account of his time within the spy service.

His comments are embarrassing for Paris as they add fuel to Teheran's claims that Miss Reiss was part of a Western plot to topple the clerical regime following President Mahmoud Ahmadinejad's disputed re-election last June.

Miss Reiss was seized as she tried to leave Iran on July 1 and charged with acting against national security by participating in opposition protests, collecting information and sending pictures of the demonstrations abroad.

She admitted as much under the duress of a televised show trial and after spending six weeks in Iran's dreaded Evin prison.

The Iranian Embassy in Paris long insisted that Miss Reiss was not as "innocent" as Paris claimed and had not been arrested "by chance".

Nevertheless, on Saturday a Teheran court instantly commuted her two five-year prison terms to a fine and returned her passport.

President Sarkozy said her release was mainly thanks to the "active role" of Brazil, Senegal and Syria.

But questions were raised over the timing of the release of two Iranians held in France.

The first, an engineer, returned to Iran last Friday after France refused to extradite him to the United States, where he is suspected of illegally buying equipment for nuclear military use.

An expulsion order for the second was signed yesterday. Ali Vakili Rad is serving a life sentence in France for the 1991 murder of Iran's last prime minister under the Shah.

He was convicted in 1994 of strangling Shapour Bakhtiar and stabbing him to death with a kitchen knife in the ex-premier's Paris flat.

Mr Rad has served the minimum 18-year term and a court is expected to order his release today.

Bernard Kouchner, the foreign minister, insisted that there had been "no horse trading" with Iran to secure Miss Reiss' freedom. But an interior ministry source said that it had been told not to sign Mr Rad's expulsion order until Miss Reiss was released.

"I think the government would do well to explain itself, to speak clearly rather than denying the obvious," said Benoit Hamon, the opposition Socialist party spokesman.

Political observers said Miss Reiss’ release could be party of a last-ditch attempt by Iran to stave off UN Security Council sanctions for its lack of transparency over its nuclear programme.

Western powers accuse Iran of attempting to develop nuclear weapons under the guise of a civilian nuclear program.