How did he play?
This loan didn't really work out well so far for Marlon. Though from the games I've seen he wasn't really that bad, it was more a problem of the whole team defensive vulnerability. I didn't follow Nice much last season, did they also play with 3 at the back?
Also, conspiracy theory. Is it possible that Favre is intentionally trying to ruin them so he'd get sacked? IIRC he already agreed to terms with Dortmund last summer but Nice didn't let him go. Maybe he doesn't want to be there anymore.