Theoretically, that is correct. However, there's still a law against "furthering prostitution" in the German penal codex. A cabdriver recommending a brothel risks losing his license and paying a severe fine.
That special unemployment law is very new, effective only since this year, and it's still in a test phase. Of course, the legislative couldn't foresee every fringe case, but that woman has a good chance to win a pioneer case. Layers will probably fight to represent her in court for free. Cases like that make law history.
Prostitution being legal just means that nobody can be punished for being a prostitute or a customer, not that anybody can be forced into prostitution. Besides, prostitution is legal since decades here, only the "moral clause" was revised a few years ago, in order to curb illegal prostitutes (not registered/controlled), and probably to gain more tax revenue...