Amazon Returns: French Collection Address and returns administration

I have a problem which I hope that someone in the pph community can solve for me.

As a business we sell on all of the international amazon sites including amazon.fr. Whilst we dispatch many of the products we sell directly from the UK, we also send some products to a French Amazon warehouse so they can fulfill the products on our behalf (Its call FBA - Fulfillment by Amazon).

The problem I have concerns the rejected, customer returns and faulty goods from this process (Collectively called unsellable goods). Whilst Amazon.fr will ship them back to me, they will only ship them back to an address in France which I don't have. Nor will they allow me to collect the goods from their warehouse.

So, here's the very simple job. I need an address in France to which I can instruct Amazon to send my unsellable goods. Once they have arrived in this location, I will arrange for a collection from there and back to the UK.

Amazon are very bad at estimating when a delivery will be made so the address in question should an office or warehouse - somewhere that is open all day on week days.

Whilst this is initially a one off job, we will probably recall our amazon unsellable stock every 3 months using this method we would also like to provide our french customers with a return address in france in the future.

Can anyone help?