In and around town a map is a bit academic this year due to the massive scale of roadworks where they are building the tram system. But to answer your question, there is a French map series called Serie Bleue (like our Ordnance Surey) , and number 1719E covers LM town and the track area at 1:25000. It doesn't show street names though, if that's what you are after. I think I got my via the internet for a fiver or so.