Shortage of workers?

For what? They have no impending war machines they need to build in rapid time. They're a static at-peace nation. They need only slightly less workers each day than the day before, as technology improves.

If they had a population drop-off... They'd need less workers to satisfy the demands of less people. If they had a population boom to need more workers... They have more workers right there: it's the population boom itself, that's workers. It's amazing how society balances itself out REALLY well, generally speaking. Need more farmers? It's probably because you have more people needing food... who can farm. Need more textile workers? It's because you have more people needing clothes... who can make clothes. And one person, with modern techonology, can contribute the efforts of several dozen if not more.

If Germany is planning on going to war, the only reason why you'd need an influx of workers as a country, they should declare that intent.