I may have recommended this when it first came out, but season 3 (final season) just dropped and I had to put in another plug. Just an excellent series. One of the best Netflix has ever done. It's their first German series. As with all foreign language stuff, I highly recommend watching in the original language with English subtitles.
The series is very intricate, and can be confusing at times if you don't pay close attention, as it does time travel jumps and also jumps between alternate Earths. The casting is excellent, as well as how well they matched up actors to play older and younger versions of their characters.
I also think this may be the very best thought out final episode of any series I have ever watched. They knew they were only doing three seasons and the final episode was just well done - both in content and how perfectly it tied up loose ends . Especially for a series that involves time travel, which so often becomes a mess of plot holes. No "WTF was that supposed to mean?!?" or anything like that. Everything came together logically and cleanly.
Anyway, this is a gem in Netflix's productions, which seem to have about a 100 to 1 ratio of crap and good stuff.