Germany is probably bad option within EU. I would recommend Bulgaria: flat tax rate 10% on corporate income and capital gains. Considerably cheaper office and accounting cost.
Note that registering a company in another country doesn't necessarily stop your local government from taxing it. Especially if the owners and employees stay in your country.
No, and dealing with the government is quite an adventure, even for natives (as I am). I certainly do not recommend, unless you have a Bulgarian native co-founder or/and lots of money to spend on good accountants/representatives.