PARIS (Reuters) - Renault Chief Executive Carlos Ghosn came under pressure after a dramatic climbdown and public apology following the collapse of an investigation into industrial espionage at the French carmaker.

Socialist Party boss Martine Aubry told France Info radio on Tuesday she thought Ghosn should take responsibility for the debacle, which has gripped France since news of executive sackings broke in January.

"When an employee makes a mistake in a company, he does not have to apologize -- he is out," she said.

Government spokesman Francois Baroin also hit out at how the matter had been handled by Renault, which is 15 percent state-owned. "We must take all the consequences ... from the incredible amateurism, and the indignity, and the attack against these men," Baroin told LCI television.

Renault bosses had pledged on Monday to forgo their bonuses after the Paris prosecutor said the espionage case was unfounded. Renault apologized to the three falsely accused executives and offered to reinstate and compensate them.

Ghosn told prime-time TF1 television news on Monday he had refused to accept the resignation of his right-hand man Patrick Pelata over the "sorry episode," as he "did not want to add one crisis to another."

Bertrand Rochette, one of the three men wrongly fired, said in a statement he had not yet been contacted by Ghosn, either directly or through his lawyers.

Renault, whose alliance partner is Japan's Nissan Motor, fired the three men in January on suspicion of industrial espionage. The three men denied wrongdoing from the start and began legal action against the carmaker.

A Renault security manager was on Sunday placed under investigation for suspected fraud concerning the spying allegations.

"Renault is pressing charges and has filed for a civil action, in the case of organized fraud," Renault said on Monday.

Renault also pledged to overhaul its governance, including a move to have its security division report directly to the executive committee, after an internal audit of what went wrong.

(Reporting by Patrick Vignal, Thierry Leveque and Gilles Guillaume; Writing by Helen Massy-Beresford; Editing by David Holmes)