Good question, and one I’ve asked for the same reason. My view is that it’s a new document so should have its own issue number, but when you up-issue the English version and get it re-translated that will also bump the french issue number.
You will need to keep a record of what issue number of the original was used for the translation somewhere, and the issues will get out of sync, but as I said, they are different documents.
I had to deal with about 5 different languages once!