Article published on the 2008-05-20 Latest update 2008-05-20 13:36 TU
Chen was named as a suspect in the corruption case in 2006 but could not be prosecuted while he was president.
His wife, Wu Shu-chen, is already on trial for corruption and forgery in connection with the same case and several leading members of the Chen's Democratic Progressive Party (DPP) face other corruption charges.
Chen admits using false receipts to claim expenses but insists they were to fund "secret diplomatic missions". Prosecutors have found that over 30,000 euros have been spent on diamond rings and other luxury items for his wife.
Taking the oath of office, Ma called for closer links with mainland China.
His Kuomintang party, which won recent elections after eight years in opposition, opposed Chen's increasing hostility to the People's Republic.
The new president called for a resumption if high-level dialogue and said that Beijing and Taipei, who both officially regard themselves as the Chinese government, should "reconcile and cease fire" to help regional stability.
But he repeated a promise not to discuss reunification with China.
Ma also expressed condolences for the vicitms of the 12 May earthquake in south-west China.