Here's the problem:
1. Anyone who's paying attention can see that 95% of the migrants who came to Germany in 2015 are going to integrate into the German social welfare system, and probably 50% will never leave it.
2. This is going to piss off working- and lower-middle class Germans, who will still have to work 40 hours a week to make a wage only 20% higher than welfare. Uwe says: 'Why do I have to I bust my ass working in some shitty supermarket for an asshole boss while Firduz hangs out on the street corner getting free money from the government for doing nothing?'
The answer: Universal Basic Income. Abolish Germany's ludicrously complex welfare system, and just give everyone, say, € 900 per month. Enough to subsist on, but not much more.
This plan will have some side-effects, of course, but it won't be such a huge change, since everyone in Germany is already entitled to a basic income -- they just have to prove they're unemployed and have no more assets. Under the new plan, everyone gets it. 95% of the useless welfare bureaucracy will vanish, providing huge savings to the German state.
Most importantly, UBI will remove, or at least greatly reduce the envy factor. Uwe will probably continue to work, since the UBI won't pay enough for any luxuries, such as a private washing machine, cars, or vacations. But since he is also getting what Firduz is getting, he will feel much less resentment.
If the SPD had any sense at all, it would stop futzing around with idiotic nanny-state schemes nobody cares about (sexist advertising) and come out loud and defiant in favor of UBI.