You have Japanese smartphones in stock. More information here about selling Japanese smartphones on BackMarket:
You can create your Japanese smartphones using a CSV file.
In the file, you need all the columns you need to create an ad.
List of fields:
Noisy camera: Warning! This is the field that identifies if your product is a Japanese version or not. If it is the case write True.
Once the CSV is ready to be imported, you can go to your Back Office on the "offer" section: https://www.backmarket.fr/bo_merchant/listings and click on the "Action" button then "import offers".
If you wanna do that on different countries at the same time, you just have to add a 'lang' column to your file and specify, for each line, the country in which you want to update.