Rent apartment

Priscilla is part of the forum team and lives in Mauritius. Therefore I will answer your question instead:

Whether a German landlord rents out an apartment to you, and what kind of financial guarantees he/she wants for it, is entirely up to him/her.
But most landlords of course prefer to avoid risk and thus would prefer somebody with proven an stable income within the country.
Dpending on how flexible the landlord is - and how many other candidates he/she can find in the town you want to live - it might be possiblke to negotiate here. For example, you could offer to pre-pay the rent for a certain period (6 months, o a year) to alleviate the worries.
(Please note that many landlords also dislike families with many kids - so having FIVE of them puts you in a disadvantage. You also need a fairly big apartment that will cost a lot.)