Completely off topic and asking for a friend (one of those internet friends I've never met...)
"my French friend of longstanding, S, has a daughter (C) who is coming to Heriot-Watt on an Erasmus exchange starting in January for one Uni term. She's keen to make the most of the opportunity to improve her English and S asked me if I could help her find a host family. Wondered if you might know anyone who'd be interested in a temporary French lodger?"
Any takers? I can't speak to any of the people involved so it's just a shot in the dark here, shout if you might be interested or have any more systematic suggestions for finding lodgings for Erasmus students