Complex sentence: In 2017, when federal elections took place in Germany, the largest donation to a political party was provided by Dommermuth, Euro 500,000 Euro to the CDU, Germany's conservative party.
Split into simpler sentences: In 2017, when federal elections took place in Germany, the highest donation to a German potitical party was provided by Dommermuth. He donated 500000 Euro to the CDU, Germany's conservative party.