Really depends where you want to be in Lyon (where will you be working/studying?)

For a reasonably price flat in Lyon, then avoid Lyon 6, but you can look for somethign either in Lyon 3 or Villeurbanne.

You can try the sudent guide: just google for "Lyon Campus pages guide"

If you are not in Lyon to visit flats by yourself you may want to ask one of the so called "Regies" to help you. See on qype (co.uk/fr716-lyon/categories/425-rental-agency-in-lyon)

Otherwise some small ads can be found on web sites like pap, bonjour,...

Good luck and let us know when you arrive here!

Mathieu
(was expat in Bristol, back in Lyon now)