Former EADS chief Noel Forgeard was detained in police custody for questioning on Wednesday as part of a probe into possible insider trading at the European aerospace giant, French police sources said.
Under French law, such questioning can last a maximum of 48 hours and may or may not be followed by an audience with a judge who can decide whether to order a formal investigation.
The EADS insider trading probe was triggered by worsening delays to production of the A380 superjumbo, which sliced a quarter off EADS stock in June 2006.
A number of EADS executives including former co-Chief Executive Noel Forgeard exercised their right to sell stock options in March 2006 but the deals fell under the spotlight when EADS' planemaker unit Airbus announced serious production difficulties with the A380 superjumbo in June that year.
Forgeard as well as EADS and other current and former officials at the company have all denied any wrongdoing.