Give per-language access to user with Entity Translation on D7

Hi all,
I come here after hours spending on the website & forum, but I did not find a solution to my problem. I hope somebody here would be able to help me (or tell me it is not possible).

We are working on a D7 website, which on is multilingual. We are using Entity Translation because it is the newer method and because we can keep only one node and not one node per language.
Everything is nice and the site is working, but now we want to define backoffice users that have only access to their languages. We have already tested multiple modules (Translation access, Node translation Access, Language Access, ...) but none of them meets our needs :/
We'd like that users can only access to content (nodes & taxonomies) of their languages, update it, create only content in these languages, and translate content to these languages.

Is there a solution for Entity translation based website ?

Thanks in advance and have a nice day !
Aurélien