Moa Hofer

Hello. I have a question regarding how to invoice a buyer when we sell an accordion for someone, on commission. We have called the tax office but even their expert cant help us. We have an accordion business and was approached by a man who wanted us to sell his accordion for 1.000 EUR. We have now found a buyer but we don't know how to invoice the buyer. The buyer doesn't know its a commission sale and assume she is going to receive an invoice from us, but we cant put 21% BTW on it as its not us selling it. Shall we put 0% BTW on the buyer invoice nd mention on the invoice that its a commission sale and when we invoice the man/seller we deduct 10% commission and put BTW on that invoice? We are a little bit confused, so help would be great. Thanks in advance. Kind Regards - Moa