We had a fortnight in Marseillan last year and we're going again at the end of this month. Lovely place to be based for a summer holiday, but it's very flat on the coast, and I mean really, really flat. There are undulations, but not of the Brittany and Normandy variety and few proper hills. Further inland are more inclines and the occasional mini col. I expect it's pretty quiet out of the holiday season. We're taking our own bikes this year, rather than hiring doubtful, ill fitting mtbs so I'll have a closer look and report back. That said, I suspect your idea of a steep incline doesn't quite coincide with mine!