FRANKFURT - Thyssenkrupp on Thursday said it was filing a complaint with a European court to dispute an antitrust decision that blocks a planned joint venture with Tata Steel.

The complaint to the General Court of the European Union - seen as a symbolic move - comes after the Commission in June vetoed plans to create Europe's second-biggest steelmaker, fearing it would overly hurt competition.

The Commission was most concerned about the two companies' combined position in the area of automotive and packaging steel, resulting in a remedy proposal Thyssenkrupp said would have been sufficient. Brussels disagreed.

"In its competitive assessment of the product groups of packaging steel and hot-dip galvanized steel for the automotive industry, the Commission has for the first time set out a restrictive market definition that unduly extends the scope of the existing competition law," Thyssenkrupp said in a statement.

It was already clear in early May that Brussels would block the deal, causing a strategic U-turn at the group which includes a planned stock market listing or sale of its elevators division.

Thyssenkrupp's steel division - Steel Europe - is now expected to remain part of the group in the long-term, Thyssenkrupp has said, though it has not ruled out partnerships or the sale of a minority stake.

(Reporting by Christoph Steitz; Editing by Michelle Martin) ((christoph.steitz@thomsonreuters.com; +49 69 7565 1269; Reuters Messaging: christoph.steitz.thomsonreuters.com@reuters.net))