Swiss to pay 2 bln Sfr for German tax deal-paper

* Upfront payment less than 10 bln Sfr originally demanded

* Deal expected on Wednesday

* Swiss president says banks have no interest in untaxed assets

ZURICH, Aug 7 (Reuters) - Germany has agreed that Swiss banks will only have to pay 2 billion Swiss francs ($2.6 billion) as an upfront payment to seal a deal on Wednesday to regularise untaxed money stashed in secret accounts, a Swiss paper reported.