Most of the examples you cite are tax evasion, not avoidance. If you use the company car privately you need to pay taxes on it. They may even require you to log your tours (Fahrtenbuch) if they don't believe you.
If you rent out the office in your house to your own company for a too high price they will investigate you for "verdeckte Gewinnausschüttung".
There are of course margins to play with in which you can probably hide a lot of money, but generally this is tax evasion
If you rent out the office in your house to your own company for a too high price they will investigate you for "verdeckte Gewinnausschüttung".
There are of course margins to play with in which you can probably hide a lot of money, but generally this is tax evasion