700,000 citizens, not eligible voters - some are kids. Not that big a voting block c. one percent of the population.  Also note that many German 'Turks' are actually Kurds.  
There's been considerable conflict in the CDU over whether to court the Turkish vote. On the one hand they're pretty damn socially conservative - natural CDU constitutency. On the other hand... CDU doesn't like foreigners. Though on the third hand I suspect that the minority of 'Turks' that are citizens aren't perfectly representative of the Turkish and Kurdish population of Germany - probably more assimilated for one thing.

I didn't post on it at the time but I remember reading last week that some CDU leaders were explicitly calling this election one between the 'Christian West' and multiculturalism.  
Rub eyes, replace 'multiculturalism' by 'Asiatic Bolshevik hordes' and you're straight back to fifties CDU.