Von Beust was a popular mayor and was seen as the guarantor for the coalition government .
The relationship between the Christian Democratic Union and the Green Alternative List has been strained since the former Mayor Ole von Beust announced he was stepping down in July .
Ole von Beust   was a popular Ole von Beust and was seen as the guarantor for the coalition government .
The relationship between the Christian Democratic Union and the Green Alternative List has been strained since the former Mayor Ole von Beust announced he was stepping down in July .