FRANKFURT, June 14 (Reuters) - Thai retailer Central Group agreed to acquire the assets it has not already secured in KaDeWe Group, a chain of landmark department stores in Germany, part of tycoon Rene Benko's folded property empire.

Central purchased the eponymous Berlin luxury department store KaDeWe in April, saying at the time it would seek to also buy the two other stores of the portfolio, Alsterhaus in Hamburg and Oberpollinger in Munich.

Central would continue to run the stores and would now seek to renegotiate the rent agreements for the retail outlets, administrator Christian Graf Brockdorff said in a statement issued by KaDeWe Group, without disclosing financial terms.

Signa, the property empire founded by tycoon Rene Benko, has been one of the biggest casualties of Europe's real estate crisis, with creditors filing claims worth billions of euros.

The group's holding company, which sits at the center of a web of hundreds of firms, has declared insolvency, as have its two most important units, Signa Prime and Signa Development.

($1 = 0.9369 euros) (Reporting by Ludwig Burger, Editing by Rachel More)