Hi j_cool,
in the pagesource of each channel of that site you can find a streamlanguage info.
Code:
http://play.tv/live-tv/908/i24-news-english/
"streamLanguage":"fr"
http://play.tv/live-tv/30/fashion-tv/
"streamLanguage":"en"
If you check that first then you know what language you can use to call it with language paramter for the json link.
If the language dosent work then you get 400 Bad Request as response back instead of 200 OK.
If I see it right then only fr & en language types are used.Just switch to other language (en or fr) if one of them did fail (400 Bad Request) and and request json link again.Just try it again.
greetz