Leading chemical maker Kyowa Hakko Kogyo Co. has filed a complaint with the Luxembourg-based Court of Justice claiming the European Commission broke a promise when it calculated a price-fixing fine imposed on the company, the firm said Tuesday.

The Tokyo-based company said the complaint, filed before the European Union court on Friday, challenges the fine imposed by the commission, not the charges themselves.

Kyowa Hakko is one of five companies ordered by the commission in June to pay fines for operating a lysine cartel in Europe between July 1990 and June 1995. Lysine is a kind of amino acid used in animal feed.

The commission fined Kyowa Hakko 13.2 million euros (1.3 billion yen), based on a new method of calculation adopted by the commission in January 1998.

However, the company says the commission had promised it would use the old method, under which the fine would have been as much as 1 billion yen less.

"We fully cooperated with the commission in investigating this case on the premise that it would apply the traditional calculation method. However, the commission applied the new rule to us, which was publicized after our company started cooperating," the company said.

The four other companies involved are Japanese firm Ajinomoto Co., Archer-Daniels-Midland Co. of the United States, and South Korean firms Cheil Jedang Corp. and Sewon Co.

Archer-Daniels-Midland was fined 47.3 million euros, Ajinomoto 28.3 million euros, Cheil 12.2 million euros and Sewon 8.9 million euros.