A decade ago, as Germany was grappling with an influx of more than a million migrants, the small town of Altena saw an opportunity to reverse years of population and economic decline.

The industrial town in western Germany made national headlines in 2015 when it volunteered to take in 100 more migrants than required, becoming a model of Chancellor Angela Merkel's pledge: "Wir schaffen das," or "We can do this."

But while there have been benefits for both sides, three current and former town officials have said migration wasn't a panacea.