Amadeus, the IT travel company, has been rebuffed in its efforts to get GDS surcharges levied by Lufthansa declared illegal.
A judge in the Hamburg District Court has ruled that the charges which the German national carrier has levied on the GDS since July are not discriminatory.
The Madrid-based GDS said it planned to appeal against the ruling.
In a statement Amadeus said: "Amadeus asked the Hamburg District Court to prevent Lufthansa from applying a surcharge which Amadeus believes discriminates against its agencies.
"The court issued a preliminary decision not to grant this relief so Lufthansa may continue to surcharge Amadeus agencies.
"We intend to file an appeal once we have analysed the reasons for Friday's preliminary judgement.
It is, of course, Amadeus' objective to find a solution that is agreeable to travel agents and travellers. We remain 100% committed to this objective."
Lufthansa welcomed the ruling adding the court decision supported its view of the case.
The row between Amadeus and Lufthansa, which owns an 11.5% stake in the IT company, dates back to January when the airline and its sister carrier SWISS announced plans to impose surcharges on certain types of tickets when booked through a GDS.
Other GDSs, including Sabre, Galileo and Worldspan, signed up to deals with Lufthansa to exempt their agents from the charges.
But Amadeus, the dominant GDS in Germany, did not reach any agreement with Lufthansa despite exhaustive talks.
Lufthansa/SWISS began levying the new charges on July 1.
Fares went up by €15 one way or €30 return on all tickets bought in Germany or Austria.
But the carriers have continued to make available the previous lower fares.
They are called "preferred fares" and are the subject to a surcharge if booked through a GDS.
It is this surcharge that Amadeus is opposing.
A Lufthansa spokesman said the judge in Hamburg had yet to deliver his written verdict.
Both sides are expected to make fuller statements when the written verdict is published.
Visit www.amadeus.com and www.lufthansa.com.