In a ruling that could affect the way planes are maintained and inspected, the court said the US airline and a welder were to blame for a small metal strip that dropped off a Continental aircraft onto the runway, rupturing a tyre and causing the crash that killed 113 people.
The airline, now United Continental Holdings following a merger, and aerospace group EADS must split 70-30 any damages payable to families of victims, it said.
The verdict exposes Continental and EADS to damage claims that could run to tens of millions of euros if insurance companies seek reimbursement for sums already paid.
The crash ended an era of supersonic travel between London, Paris and New York. Operators Air France and British Airways took Concorde out of service in 2003 after safety concerns hit passenger numbers.
Continental was fined €200,000 (£169,400) and ordered to pay Concorde’s operator Air France €1m in damages. Welder John Taylor was given a 15-month suspended prison sentence for having gone against industry norms and used titanium to forge the piece that dropped off the plane. Continental said it would appeal.