If RMB is converted into Euro, and the amount is large, you have to make an appointment with the Bank of China. It takes time for the bank to prepare foreign currency cash for you, because a large amount of foreign currency cash will not be deposited in the bank.
If you change euros into RMB, you can do it at any time during business hours, without making an appointment. A certificate of origin is required for bulk exchange, such as bringing it in from abroad.
Remember to do the above two businesses, you need my ID card.