Here the most popular third language is Spanish, by far. German used to be the preferred choice up to the 1990s, but it's showing a steep decline now. All the good students used to take German as their first or second foreign language, however this is not the case anymore.
The demand for German in the business world is very high, though. I think most parents are aware of this fact but they still let their children pick Spanish. Looking back now, my classmates who took German in middle school all had engineer parents, which is quite interesting... I suppose Spanish has the reputation of being a very cool language and its appeal overshadows the prospects that German supposedly offers. Or perhaps it's because most people don't think that knowing German is that beneficial altogether, which would imply that Germany and Germans are not perceived as being better off socially. I can't really say, the answer could very well lie somewhere in the middle and we also have to take into account the undisputed predominance of English, both in France and in Germany.
Then, there's also a sort of vicious circle at play. The fact is that we have a lot more employable Spanish teachers while qualified German language educators are a dying breed nowadays. To give you an example, there were 245 vacant German teacher positions last year in France. However, only 136 test takers among the 233 persons that sat the exam actually met the standards. This means that 44% of the positions remained vacant! And the same scenario repeats itself year after year. German is literally the only subject (along with Classics) where we can't find enough candidates to fill up the ranks (even mediocre but, you know, okayish candidates).
So for the Ministry of National Education it is more practical to streamline language education by focusing on English and Spanish. This makes the management much simpler and economical (and the top schools can still offer German classes, anyway
To conclude, I suspect that most people don't really pay attention to the social standing of the third language they choose to study. This could be due to the fact that all languages besides English are deemed to be secondary. After all, if you have to learn a third language for fun, why not take Spanish? Some status conscious, well-informed and / or ambitious parents might still make sure their kids pick German (and Latin, and further Maths), though.
We could still dig deeper into the subject, because I believe there are languages which people tend to shun actively (or maybe it would be more correct to say that those are not thought of as languages that one would actually learn and become proficient in or which you might learn for adventure but cannot expect to benefit from socially).