Taxes for commission based business model

[Loic6]

Hi, I am new there and my team and I are faced with a significant issue : taxes 

We are a French platform that connect sellers and buyers of second hand luxury goods (C2C). for this service we collect a commission on which we collect VAT. There is no VAT on the transaction of the products themselves because the buyers and sellers are individuals. We sell to every countries. 

But Shopify doesn't do commission-based business model, and so we need to do some work around : 

- For France and Europe, to manage the VAT on commissions only, we have created specific collections and created tax overrides. It seems to work out. 

- BUT for non-EU transactions, I am afraid that solution doesn't work : we cannot create tax override as the company do not have Sales Tax ID. 

What would you recommend, because for non-EU transaction we are stuck ? 

Thank you !!