German labor law has some features that might interact in interesting ways with startups. Germany lacks employment-at-will; it appears that disputed terminations can easily become lawsuits there (but German law also seems to have orderly mechanisms for resolving these disputes, which boil down to mandatory severance). German law has what appears to be a strict policy on hours worked per week and per day, and on worki…
The working hours thing, for better or worse, is broadly ignored in software companies. That said, hours aren't as extreme as in many American companies.
For the parental leave, that only applies for companies with more than 15 employees, so the startups that it would affect are going to be more established. And while taking a year off is common, it's very rare for more to be taken with intent to return to the job.