Is Zakat obligatory on inherited wealth amounting to 4000 Euros, and how much would it be?

There is no Zakat due on rented shops. Rather, Zakat is due on their rental income if it reaches the nisab and a hawl (full lunar year) passes over it. The nisab is equivalent to 595 grams of silver. If the rent is spent before a year passes, then no Zakat is due on it. The obligatory amount is one-quarter of one-tenth (2.5%), by consensus. As for the amount mentioned in the question (four thousand euros), it is to be divided among all the heirs. If each heir's share reaches the nisab, then Zakat becomes obligatory on it once a hawl passes from the day of the deceased's death.