* Placed moles in U.S. computer firms in Paris and Silicon Valley to pass along breakthrough technology.
* Posed as non-defense customers to obtain classified U.S. "stealth" technology for France's aerospace industry.
* Recruited French nationals employed by the U.S. Embassy in Paris to spy on visiting American VIPs.
* Exploited inside knowledge of an intended U.S. dollar devaluation to make a killing on international currency markets.
"The French are the most predatory service in the world now that the old Soviet Union is gone," former director of central intelligence Stansfield Turner said bluntly.
Many other countries conduct industrial espionage. Japan, Britain, South Korea, Taiwan and China also were named in April hearings before a House Judiciary subcommittee as countries that have targeted the United States for spying.
Their quest is not for the old Cold War stuff such as arms-talk leaks and tank-armor specifications. Rather, they are seeking economic targets such as fiber-optic technology, marketing strategies and the numbers inside sealed bids for international business.
"The French espionage effort is the most systematic, most widespread, most aggressive and most difficult to deal with," said Peter Schweizer, author of the forthcoming book Friendly Spies.
Pierre Marion, former head of France's equivalent of the CIA, the Direction Generale de la Securite Exterieure (DGSE), was forthright about his country's approach.
"In the technological competition, we are competitors," he said. "We are not allied."
Marion said in a telephone interview that while head of the DGSE in 1981-82, he launched a new unit of 20 to 25 spies mainly to help France's aerospace, telecommunications, computers and biotechnology industries - all partly government-owned.
That effort "has enjoyed the highest priority for at least the last decade and probably longer," Gerald Burke, an international security consultant, told the Judiciary subcommittee last spring.
For many years, a VIP travel coordinator at the U.S. Embassy in Paris, Maria Lamant, tucked copies of the itineraries of American business visitors into her copy of Le Monde, according to French press reports. Agents reportedly used them to wire Air France seats and hotel rooms and to photograph the contents of key American briefcases.
Typically, France targets advanced technologies "that might have taken years and millions of francs to develop or perfect," wrote the Count de Marenches, head of the DGSE during 1970-81, in a recent memoir, The Fourth World War.
Voluntary spies called "honorary correspondents" sometimes help "purely for the honor," according to Marenches. In addition, young French scientists on occasion have joined U.S. firms and spied for their French competitors in lieu of military service.
Texas Instruments Inc., International Business Machines Corp. and Corning Inc. all lost secrets this way, according to congressional testimony last spring.
Recently, French engineers vouched for by their embassy here misrepresented themselves as customers to Dow Corning Corp., according to Richard Heffernan, a security consultant in Branford, Conn. Their interest: secrets of the radar- evading coatings used by stealth aircraft.
FBI counterspies discouraged them by tailing them, said Heffernan.
Dow Corning declined comment and FBI spokesman Steve Markardt termed any question about allied spying "too sensitive" for the FBI to discuss.
Laurent Aublin, a French Embassy spokesman, said allegations of French commercial spying "have never been substantiated" and "have long been denied by my authorities."
In a rare U.S. prosecution, a French computer engineer, Marc Goldberg, pleaded guilty in 1991 to two felony trade theft counts involving his employer, Renaissance Software Inc. of Palo Alto, Calif.
Goldberg was caught copying Renaissance's software source code while receiving a French government stipend for reporting on his work, investigators and company officials told the San Jose (Calif.) Mercury-News, which broke the story.
Goldberg received a suspended sentence and was permitted to return to France in March 1991 to do 1,000 hours of community service.
Until recently, U.S. counterspies generally looked the other way, security experts say, because French spies share their take on the Middle East, North Africa and French-speaking Africa.
Moreover, U.S. laws protecting trade secrets are unclear enough to deter most prosecutors, according to last spring's congressional testimony.
Is turnabout fair play? CIA director Robert M. Gates said no.
Only if a U.S. company is the object of "an intelligence operation directed specifically at it overseas," Gates told the Judiciary subcommittee, and if "we can detect that a foreign government has a hand in it," will the CIA tell the U.S. victim.
Otherwise, Gates insisted, it's up to American businesses to "size up their foreign competitors."