Paraguay is a country that welcomes foreign investment, there are many laws like 60/90(that establishes tax exonerations for certain type of investment) or maquila law that alos establishes tax benefiets for good production investments.
There is no personal income tax, corporate tax 10% over profit(once a year). VAT is 10% which is decuctible BTW.
Will posting more info on company oppening, but basically you need a Public Notary, Sociedades Anonimas is one the best ways to establish a legal entity, in terms of legal/civil/assets protection. Also you need municipal license, an accountant to take care of your declartion before treasury ministry.