Allocation of seats at the European Parliament

Who decides how many seats each member state must have in the European Parliament?

It is the European Council that decides on how many seats are allocated to each of the 25 member states in the European Parliament. Since the European Council consists of prime ministers or presidents from all member states, this means that the heads of government or state determine the allocation of seats.

The constitution says that such a decision requires the approval of each prime minister. In other words, the prime ministers must be unanimous in their approval of seat allocations in the European Parliament.