A court in the Czech Republic has blocked the country’s energy company from signing a deal with South Korea’s Korea Hydro and Nuclear Power(KHNP) to build two nuclear reactors in the European country.

The Brno Regional Court issued the preemptive ruling Tuesday, a day before KHNP was scheduled to sign the contract with Elektrárna Dukovany II, a subsidiary of the Czech Republic’s main electricity firm, CEZ.

The court said in a statement that the deal cannot be signed until the court rules on a complaint from the losing bidder, France’s EDF.

It said that if the deal were signed, the French bidder would permanently lose its chance to compete for the contract even if the court ruled in its favor later on.

KHNP won the contract in July last year after beating EDF in the tender, but EDF filed a complaint last week against the Czech Office for the Protection of Competition after the regulator rejected its appeal in the case.