France’s Caisse des Depots, often described as the armed wing of the country’s Treasury, on Friday sought to stem the mounting political outcry over its role in controversial share dealings in EADS, the Franco-German aerospace group.

The state-owned institution, which is often used as a guarantor of stable French ownership for French companies, on Friday insisted it had not been asked by the government to acquire EADS shares in April 2006, just weeks before the aerospace group announced a profit warning that sent the shares tumbling.

It also said that when it bought shares being sold by the Lagardère media group – EADS’s core French industrial shareholder, which in March decided to halve its 15 per cent holding – it had no information other than what was publicly available at the time. The CDC has said it will take legal action if it finds its interests have been damaged.

Opposition politicians and shareholder lobby groups have seized on a preliminary report from the AMF French stock market regulator, which was leaked this week to Le Figaro newspaper, suggesting the finance ministry had been aware as early as January that the aerospace group would face “a period of turbulence”.

They have accused the government of possible dereliction in duty, if it is found to have had such information but warned neither the market nor the CDC. The government denies it had any information other than what was publicly available.

The AMF report, which has been passed to the French courts, also raised the alarm over possible insider dealing on a “massive scale”. The AMF continues to investigate transactions by a host of past and present senior executives at EADS and the two core industrial shareholders, Lagardère and Daimler of Germany, ahead of the June warning. The government did not sell any of its shares.

The revelations come at a delicate time for Nicolas Sarkozy, the French president, who is attempting to push through labour market and social reforms.

Meanwhile, Thierry Breton, former French finance minister, was on Friday summoned to testify before a Senate committee investigating the allegations of insider trading.

Mr Breton said he had been unaware of the CDC’s decision to acquire the Lagardère shares.

Tom Enders, the German Airbus boss, also sought to redress a crisis of confidence in parent group EADS by writing to the AMF to complain about the leak of the report. Mr Enders was listed as one of the executives under investigation, after he sold shares in November 2005. Mr Enders wrote to the board of EADS to reiterate his innocence.

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