I looked at this about 5 years ago, so probably out of date. What I found was that it was hugely dependent on the intention or usage case. e.g. If the search was for technical information then English was common, if it was for anything local it was almost always in German (in fact an English search for a "local search" category was a great indicator that the person was not German).

As for you specific example (which we try to avoid here), I've seen evidence that suggests that Google is able to distinguish those that don't mind foreign results - but that's a personalisation issue which requires a very strong bias to overcome the mother tongue pages. Given that the example is very broad and in German I'd put money on German versions appearing first, as there will be many good matches; English is likely to pop up when BOTH there are few decent German pages and teh user has a history of English queries. Do not base a business of getting German visitors to a site with information that pertains to any location if it is written in English. If you want to cate for English people looking for tourist stuff in Germany then English is great...

Thanks! Interesting data.