Air France is suing Continental Airlines over its alleged role in the July Concorde disaster that killed 113 people and grounded the supersonic aircraft.

French investigators believe a stray strip of metal which had fallen off a Continental DC-10 punctured a tyre on the doomed Air France Concorde during its take-off from Paris airport, triggering the tragedy.

A Continental DC-10 took off just before the Concorde on its doomed July 25 flight

"A piece from a Continental Airlines plane caused the Concorde accident," an Air France spokeswoman said, confirming the lawsuit.

The legal case was lodged at a commercial court outside Paris.

The spokeswoman added that under the civil aviation legal code, airlines were responsible for damage caused by any pieces which fell off their aircraft.

Continental acknowledged earlier this month that the metal piece could have come from one of its planes but in a recent statement said "at this stage of the investigation, there is however no conclusive evidence that Continental Airlines is involved in the Concorde crash."

Continental, in its statement, said the American carrier would continue co-operating with French investigators and again expressed its sympathy for the victims' families.

The crash killed all 109 people on board the Concorde and four people on the ground.

A German lawyer representing some of the victims said that he was also suing Continental Airlines.

Christof Wellens, who represents 20 families, said from his Moenchengladbach office that his lawsuit would likely be filed in a Texas court.

He declined to name a figure for damages sought or say exactly when he would file the lawsuit. Wellens said the airline would be "clearly negligent" if it is confirmed the piece of metal came from the Continental jet.

A preliminary report on the Concorde crash was issued on August 31 by France's Accident and Inquiry Office.

It described how a left forward tyre on the plane was destroyed, probably by a stray piece of metal on the runway, sending huge chunks of rubber toward the fuel tanks in the Concorde's delta-shaped wings.

They believe that caused a fuel leak that sent flames shooting out behind the plane on take-off.